Appearance-driven automatic three-dimensional modeling

ABSTRACT

Appearance driven automatic three-dimensional (3D) modeling enables optimization of a 3D model comprising the shape and appearance of a particular 3D scene or object. Triangle meshes and shading models may be jointly optimized to match the appearance of a reference 3D model based on reference images of the reference 3D model. Compared with the reference 3D model, the optimized 3D model is a lower resolution 3D model that can be rendered in less time. More specifically, the optimized 3D model may include fewer geometric primitives compared with the reference 3D model. In contrast with the conventional inverse rendering or analysis-by-synthesis modeling tools, the shape and appearance representations of the 3D model are automatically generated that, when rendered, match the reference images. Appearance driven automatic 3D modeling has a number of uses, including appearance-preserving simplification of extremely complex assets, conversion between rendering systems, and even conversion between geometric scene representations.

CLAIM OF PRIORITY

This application is a continuation of U.S. Non-Provisional application Ser. No. 17/194,477 (Attorney Docket No. 513336) titled “Appearance-Driven Automatic Three-Dimensional Modeling,” filed Mar. 8, 2021 which claims the benefit of U.S. Provisional Application No. 63/116,294 (Attorney Docket No. 513301) titled “Appearance-Driven Automatic Three-Dimensional Modeling,” filed Nov. 20, 2020, the entire contents of both are incorporated herein by reference.

BACKGROUND

Synthesizing images of objects with complex shapes and appearances is a central goal in computer graphics. The problem can be broken down into choosing suitable representations for shape and appearance of the objects, modeling a three-dimensional (3D) scene according to the chosen representations, and finally, rendering the scene efficiently. Creating a shape and appearance model for a particular 3D scene is inherently an inverse problem: seeking representation that will, when rendered, result in a two-dimensional (2D) image that appears as desired. Over multiple iterations, inverse rendering is used to iteratively recover a shape, lighting, and material properties of a 3D model based on 2D images. Inverse rendering is challenging because the operations used to render the 3D model to produce the 2D images cannot simply be performed in reverse to generate the 3D model from the 2D images. Therefore, conventional modeling tools turn the problem around: instead of providing the user with means to specify the image they want, conventional modeling tools provide tools for editing the scene representation, leaving the modeler to manually modify the scene representation iteratively to achieve their goal. There is a need for addressing these issues and/or other issues associated with the prior art.

SUMMARY

Embodiments of the present disclosure relate to appearance driven automatic three-dimensional (3D) modeling. Systems and methods are disclosed that enable optimization of a 3D model comprising the shape and appearance of a particular 3D scene or object. In an embodiment, triangle meshes and shading models are jointly optimized to match the appearance of reference 3D models based on reference images of the reference 3D models. Compared with the reference 3D model, the optimized 3D model is a lower resolution 3D model that can be rendered in less time. More specifically, the optimized 3D model may include fewer geometric primitives compared with the reference 3D model. Appearance driven automatic 3D modeling has a number of uses, including appearance-preserving simplification of extremely complex assets, conversion between different rendering systems, and even conversion between different geometric scene representations.

In contrast with the conventional inverse rendering or analysis-by-synthesis modeling tools, the shape and appearance representations of the 3D model are automatically generated that, when rendered, match the reference images. In other words, the modeler need not manually modify the scene representation iteratively to optimize a 3D model. In an embodiment, shape optimization of the 3D model is based on deforming an existing triangular mesh, relying on multiple reference images to allow higher quality reconstruction that includes materials in the representation. In contrast with approaches that train a neural network to convert a higher resolution 3D model into a lower resolution 3D model, the representation is directly generated based on image space differences.

A method, computer readable medium, and system are disclosed for appearance-driven automatic 3D modeling. An initial 3D model is processed to produce a set of images for environmental conditions specifying at least one of camera position or light position. A reference 3D model is rendered to produce a set of reference images for the environmental conditions and image space losses are computed based on the set of images and the set of reference images. Parameters of the initial 3D model are updated according to the image space losses to produce a reduced resolution 3D model having a lower resolution compared with a resolution of the reference 3D model.

BRIEF DESCRIPTION OF THE DRAWINGS

The present systems and methods for appearance driven automatic 3D modeling are described in detail below with reference to the attached drawing figures, wherein:

FIG. 1A illustrates a conceptual diagram of an appearance driven automatic 3D modeling system, in accordance with an embodiment.

FIG. 1B illustrates a flowchart of a method for appearance driven automatic 3D modeling suitable for use in implementing some embodiments of the present disclosure.

FIG. 1C illustrates a diagram of another appearance driven automatic 3D modeling system suitable for use in implementing some embodiments of the present disclosure.

FIG. 2A illustrates a conceptual diagram of normal vector and displacement mapping for a 3D model, in accordance with an embodiment.

FIG. 2B illustrates a conceptual diagram of normal vector and a new lighting scenario for a 3D model, in accordance with an embodiment.

FIG. 2C illustrates a conceptual diagram of appearance pre-filtering for a 3D model, in accordance with an embodiment.

FIG. 2D illustrates a conceptual diagram of simplification of aggregate geometry for a 3D model, in accordance with an embodiment.

FIG. 3 illustrates a block diagram of the rendering pipeline shown in FIGS. 1A and 1C suitable for use in implementing some embodiments of the present disclosure.

FIG. 4 illustrates an example parallel processing unit suitable for use in implementing some embodiments of the present disclosure.

FIG. 5A is a conceptual diagram of a processing system implemented using the PPU of FIG. 4 , suitable for use in implementing some embodiments of the present disclosure.

FIG. 5B illustrates an exemplary system in which the various architecture and/or functionality of the various previous embodiments may be implemented.

FIG. 5C illustrates components of an exemplary system that can be used to train and utilize machine learning, in at least one embodiment.

FIG. 6A is a conceptual diagram of a graphics processing pipeline implemented by the PPU of FIG. 4 suitable for use in implementing some embodiments of the present disclosure.

FIG. 6B illustrates an exemplary game streaming system suitable for use in implementing some embodiments of the present disclosure.

DETAILED DESCRIPTION

Systems and methods are disclosed related to appearance driven automatic 3D modeling. The optimized (simplified) 3D model is produced starting with an initial 3D model (e.g., sphere or reduced resolution version of the reference 3D model) and parameters of the initial 3D model are updated to produce the optimized 3D model. The initial 3D model is an initial guess for beginning an optimization process to produce the optimized or reduced resolution 3D model. The parameters are updated based on image space losses (e.g., pixel differences) between rendered images of the initial 3D model and the reference 3D model.

A differentiable renderer and non-linear optimization algorithms are used to develop the optimized 3D model by minimizing image space differences that are computed based on images of the 3D model and images of a reference 3D model rendered in similar viewing and lighting conditions. Success is measured according to whether rendered images of the 3D model are visually identical or nearly identical compared with the rendered images of the reference 3D model. As the only signals driving the optimization are differences in the rendered images, the approach is highly general and versatile: it easily supports many different forward rendering models such as normal mapping, spatially-varying bi-directional reflectance distribution functions (BRDFs), displacement mapping, and the like. Supervision through images only is also key to the ability to easily convert between rendering systems and scene representations.

In an embodiment, the generated 3D models are represented as triangle meshes with materials encoded as textures to ensure that the 3D models render efficiently on modern graphics hardware and benefit from, e.g., hardware-accelerated rasterization, ray-tracing, and filtered texture lookups. The automatically generated 3D models may be used for mesh decimation through joint shape and-appearance simplification, optimized level-of-detail generation for reduced aliasing, seamless mesh filtering, approximations of aggregate geometry, joint optimization of shape and skinning weights to produce reduced geometry for animation, conversion between shape representations, and conversion between rendering systems.

Because the appearance driven modeling technique is based on inverse rendering and non-linear optimization, it easily generalizes over different regimes while allowing joint optimization of all aspects of the representation that affect the final appearance of the optimized 3D model. Specifically, in an embodiment, the search for the shape and appearance of the 3D model is driven by image space error and the shape and appearance are simultaneously optimized. Therefore, each stage of the forward rendering model (e.g., geometry, shading, normal maps, displacement maps, transparency, and the like) can specialize for the effects that the particular stage captures best, “negotiating” how to achieve the desired outcome together. As an example, a natural division of labor between the geometry (mesh) and a normal map occurs: geometric detail is allowed to move between the representations by, e.g., locally smoothing a mesh and baking geometric detail into the normal map or other parameters of a physically-based shading model.

FIG. 1A illustrates a conceptual diagram of an appearance driven automatic 3D modeling system 150, in accordance with an embodiment. An initial 3D model 105 representation may include geometry defined by locations of vertices in 3D space that form a mesh (e.g., sphere or other geometric shape) and parameters 106. In an embodiment, the mesh is defined by other types of primitives or representations. The initial 3D model 105 is adjusted to produce a reduced resolution 3D model 110. The reduced resolution 3D model 110 is reduced in terms of complexity and/or geometric resolution (e.g., number of primitives and/or vertices) compared with a reference 3D model. In an embodiment, the number of primitives defining the reduced resolution 3D model 110 is equal or greater than the number of primitives defining the initial 3D model 105.

The parameters 106 of the initial 3D model 105 and parameters 116 of the reduced resolution (optimized) 3D model 110 may correspond to materials defined by spatially-varying BRDF. The parameters 106 and 116 may include normal vector maps, displacement maps, texture maps, skinning weights, and the like. More specifically, the texture maps may define lighting and material properties. An initial surface texture for the initial 3D model 105 may be a constant or randomized color and the colors of each texel in the initial surface texture are adjusted based on image space differences to produce a texture for the reduced resolution 3D model 110.

Environmental conditions 108 define camera and light positions used by a rendering pipeline 100 for producing each image of the images 112. The rendering pipeline 100 renders the initial 3D model 105 according to the environmental conditions 108 to produce one or more of the images 112. In an embodiment, the initial 3D model 105 is a base model that is deformed to produce a specific 3D model corresponding to each of the 2D images in the images 112. Reference images 124 are generated by rendering a reference 3D model according to the environmental conditions 108. In an embodiment, the reference images 124 comprise a video or animation sequence of the reference 3D model in motion and/or deforming. As shown in FIG. 1A, the images 112 include a rendered 3D model representation 115 and the reference images 124 include a rendered reference 3D model 125. While the initial 3D model 105 may not closely resemble the reference 3D model, after successful optimization, the reduced resolution 3D model 110 does closely resemble the reference 3D model.

In an embodiment, the rendering pipeline 100 is a differentiable renderer and, one or more operations of the differentiable renderer are performed using any combination of a graphics processing unit (GPU) graphics pipeline, GPU general computation cores, or on a central processing unit (CPU). The differentiable renderer enables operations such as rasterizing large numbers of triangles, attribute interpolation, filtered texture lookups, as well as user-programmable shading and geometry processing, all in high resolutions. In contrast with conventional rendering pipelines, the operations performed by the rendering pipeline 100 are differentiable and image space losses 122 may be propagated backwards through the rendering pipeline 100 to iteratively adjust the reduced resolution 3D model 110. In some embodiments, rendering operations may include rasterization, ray tracing, and path tracing.

An image space loss unit 120 processes the reference images 124 and the images 112 to produce the image space losses 122. Corresponding images from the images 112 and reference images 124 for each particular environmental configuration 108 are compared to compute the image space losses 122. The initial 3D model 105 is adjusted based on the image space losses 122 to produce the reduced resolution 3D model 110. The reduced resolution 3D model 110 may be further refined until the image space losses 122 are reduced to a target value. In an embodiment, the reduced resolution 3D model 110 comprises a mesh having a higher resolution (e.g., more triangles) compared with the initial 3D model 105, but the resolution of the reference 3D model is even higher resolution compared with the reduced resolution 3D model 110. In response to the image space losses 122, the reduced resolution 3D model 110 may be further tessellated during optimization to reduce the image space losses 122. As shown in FIG. 1A, the reduced resolution 3D model 110 for the particular example is represented by 3 k triangle primitives defined by vertex positions and normal vectors. In contrast, the reference 3D model is represented by 735 k triangle primitives. In an embodiment, a normal vector is associated with each vertex and the normal vector is perpendicular to a surface of the triangle primitive at the vertex.

A shaded portion of the skull shown in the reduced resolution 3D model 110 illustrates the tangent space normal vectors that are stored as a texture. The normal map for the reduced resolution 3D model 110 can be much higher resolution compared with the number of vertices of the reduced resolution 3D model 110, so that for each triangle, many different normal vectors may be read from the texture over the surface of the triangle. Using a higher resolution for the parameters is a key enabler for creating a reduced resolution version of a reference 3D model with many triangles. For example, geometric details of the mesh are baked (e.g., encoded) into the normal map texture.

The goal of the appearance driven automatic 3D modeling system 150 is to produce the reduced resolution 3D model 110 that, when rendered according to the environmental conditions 108 produces a set of rendered images 112 that closely match the reference images 124. Unlike conventional modeling systems having a goal of accurately reconstructing the reference 3D model, the appearance driven automatic 3D modeling system 150 generates the reduced resolution 3D model 110 that can be rendered to produce images that closely match images of the reference 3D model. In other words, the rendered images are processed to determine and fine-tune the geometry that defines the 3D model and there is no need to directly compare the representation of the reduced resolution 3D model 110 with the reference 3D model. In fact, the representation of the reference 3D model may be quite different compared with the representation of the reduced resolution 3D model 110.

In contrast to algorithms like multi-view stereo that must make do with a small number of reference images, appearance driven automatic 3D modeling is well-suited for applications where it is possible to programmatically synthesize reference views of a target scene under arbitrary, controllable viewing and lighting conditions. The objective function used by the image space loss unit 122 is based on visual differences and gradient-based optimization may be leveraged through differentiable rendering within the rendering pipeline 100.

More illustrative information will now be set forth regarding various optional architectures and features with which the foregoing framework may be implemented, per the desires of the user. It should be strongly noted that the following information is set forth for illustrative purposes and should not be construed as limiting in any manner. Any of the following features may be optionally incorporated with or without the exclusion of other features described.

FIG. 1B illustrates a flowchart of a method 130 for appearance driven automatic 3D modeling suitable for use in implementing some embodiments of the present disclosure. Each block of method 130, described herein, comprises a computing process that may be performed using any combination of hardware, firmware, and/or software. For instance, various functions may be carried out by a processor executing instructions stored in memory. The method may also be embodied as computer-usable instructions stored on computer storage media. The method may be provided by a standalone application, a service or hosted service (standalone or in combination with another hosted service), or a plug-in to another product, to name a few. In addition, method 130 is described, by way of example, with respect to the appearance driven automatic 3D modeling system 150 of FIG. 1A. However, this method may additionally or alternatively be executed by any one system, or any combination of systems, including, but not limited to, those described herein. Furthermore, persons of ordinary skill in the art will understand that any system that performs method 130 is within the scope and spirit of embodiments of the present disclosure.

At step 135, an initial 3D model is processed by to produce a set of images for environmental conditions specifying at least one of camera position or light position. In an embodiment, the initial 3D model is the initial 3D model 105 that is processed by the rendering pipeline 100. In an embodiment, the initial 3D model comprises a sphere. In an embodiment, the initial 3D model is a latent representation that is unobserved and inferred from image space differences. In an embodiment, the latent representation comprises a triangle mesh and a set of textures that describe spatially varying material from a physically-based shading model.

In an embodiment, a rendering pipeline produces the set of images. In an embodiment, the rendering pipeline is a differentiable renderer and image space losses are propagated backwards through the rendering pipeline to update the parameters. In an embodiment, the parameters comprise at least one of vertex locations, surface normal vectors, materials, a displacement map, skinning weights, or a texture map. In an embodiment, the rendering pipeline comprises a sequence of mesh operations, a rasterizer, and a deferred shading stage. In an embodiment, the rendering pipeline performs an analytic antialiasing operation that determines shaded pixel values based on geometric coverage after rasterization, visibility testing, and texture mapping is performed.

At step 140, a reference 3D model is rendered to produce a set of reference images for the environmental conditions. In an embodiment, the reference 3D model is rendered by a second rendering pipeline that has a different structure compared with the rendering pipeline. In an embodiment, the initial 3D model comprises a decimated version of the reference 3D model. In an embodiment, the reference images are anti-aliased and the initial 3D model is processed by the rendering pipeline using fewer samples per-pixel, compared with the number of samples used to render the reference images, to produce the set of images. In an embodiment, the set of reference images comprise an animation sequence and the parameters comprise skinning weights.

At step 145, image space losses are computed based on the set of images and the set of reference images. In an embodiment, the image space losses are computed by the image space loss unit 120. In an embodiment, the set of images and the set of reference images each include at least one image. In an embodiment, the image space losses are back propagated through the rendering pipeline to update the initial 3D model and improve visual similarity between the sets of images and reference images. In an embodiment, the image space losses are back propagated as gradients that indicate the effect of moving mesh vertex positions and adjusting other parameters has on the set of images. Operations performed by the rendering pipeline to produce the set of images are differentiable, so that the gradients may be computed for backpropagation.

In an embodiment, the image space losses are computed using stochastic gradient descent. In an embodiment, an image from the set of images and a corresponding image from the set of reference images for each one of the environmental conditions are compared to compute the image space losses. In an embodiment, the environmental conditions comprise random camera and light positions. In an embodiment, the light is a single point light source similar to a virtual photo-goniometer.

At step 155, parameters of the initial 3D model are updated according to the image space losses to produce a reduced resolution 3D model having a lower resolution compared with a resolution of the reference 3D model. In an embodiment, corrections for the parameters are generated simultaneously to update the parameters. In an embodiment, the reduced resolution 3D model comprises a first geometric representation and the reference 3D model comprises a second geometric representation that is different from the first geometric representation. The reduced resolution 3D model comprises an optimized representation of the reference 3D model that may replace the reference 3D model for games or other real-time applications.

Step 135 may be repeated, but instead of processing the initial 3D model, the reduced resolution 3D model is processed to produce at least one additional image. Steps 140 and 145 may be repeated, for the at least one additional image and at least one additional reference image. Finally, step 155 may be repeated, but instead of updating the parameters of the initial 3D model, the parameters of the reduced resolution 3D model are updated to optimize the reduced resolution 3D model over one or more iterations.

FIG. 1C illustrates a diagram of another appearance driven automatic 3D modeling system suitable for use in implementing some embodiments of the present disclosure. In addition to the rendering pipeline 100 and the image space loss unit 120 from the appearance driven automatic 3D modeling system 150, the system also includes a rendering pipeline 160. In an embodiment, an initial 3D model 165 is a sphere that is updated according to image space losses 174 to produce a reduced resolution 3D model 170. As shown in FIG. 1C, the reduced resolution 3D model 170 may be iteratively updated according to the image space losses 174 to optimize the reduced resolution 3D model 170 that, when rendered, produces images 172 that more closely resemble reference images 176 of a reference 3D model 175.

The rendering pipeline 160 used to process the reference 3D model 175 and produce the reference images 176 may be the same or different compared with the rendering pipeline 100. In an embodiment, the rendering pipeline 100 is differentiable and can produce images from 3D geometry in a forward operating pass and can also update the 3D geometry in a backward operating pass. The rendering operations may include rasterization, ray tracing, and path tracing. In contrast, the rendering pipeline 160 may perform one or more operations that are not differentiable. However, both rendering pipelines 100 and 160 generate the images 172 and the reference images 176 according to the same environmental conditions 178. In an embodiment, neither the rendering pipeline 100 nor the rendering pipeline 160 renders shadows or other global effects. Note that effects that are visible in the reference images 176 will influence updates to the reduced resolution 3D model 170. For example, when the reference images 176 are rendered with ambient occlusion or path tracing enabled, the resulting effects will be encoded into material parameters of the reduced resolution 3D model 170. Therefore, geometry of the reduced resolution 3D model 170 may reasonably approximate geometry of the reference 3D model 175 regardless of whether the rendering pipeline 100 has ambient occlusion and/or path tracing enabled.

The rendering pipeline 160 may be considered as a black box because the only information communicated from the rendering pipeline 160 and the reduced resolution 3D model 170 are the reference images that are used by the image space loss unit 120 to compute the image-domain loss. Therefore, the geometry representation defining the reduced resolution 3D model 170 and reference 3D model 175 may be different. For example, the reference 3D model 175 may be represented as a signed distance field while the initial 3D model 165 and the reduced resolution 3D model 170 are represented as triangle meshes. The different parameters for the reduced resolution 3D model 170 are jointly optimized, allowing cooperation between different parameter types affecting shape and appearance (e.g., vertex locations and normal and displacement maps and/or tessellation and textures).

The image space loss unit 120 computes the image space losses 174 for the images 172 and reference images 176. In an embodiment, θ denotes the parameters of the reduced 3D model representation (e.g., mesh vertex positions and spatially varying material parameters). The rendered images 172 I_(θ)(c,l) is a function of θ, camera, c, and light, l. The reference rendering pipeline 160 is another function I_(ref)(c,l), parameterized by the camera and light. Given an image space loss function L, the empirical risk

$\begin{matrix} {\underset{\theta}{\arg\min}{{\mathbb{E}}_{c,l}\left\lbrack {{L\left( {I_{\theta}\left( {c,l} \right)} \right)},\left( {I_{ref}\left( {c,l} \right)} \right)} \right\rbrack}} & {{Eq}.(1)} \end{matrix}$

is minimized using stochastic gradient descent based on gradients w.r.t. the parameters, ∂L/∂θ, which are obtained through differentiable rendering.

In an embodiment, a Laplacian regularizer may be used to as an additional loss term to promote well-formed meshes, using the vertex positions of the optimized reduced resolution 3D model 170. Particularly when gradients are large, the Laplacian regularizer may be used to keep the mesh surface intact. A uniformly-weighted differential δ_(i) of vertex v_(i) is given by

${\delta_{i} = {v_{i} - {\frac{1}{❘N_{i}❘}{\sum_{j \in N_{i}}{v}_{j}}}}},$

where N_(i) is the one-ring neighborhood of vertex v_(i). In an embodiment, a Laplacian regularizer term is given by

$\begin{matrix} {{L_{\delta} = {\frac{1}{n}{\sum_{i = 1}^{n}{{\delta_{i} - \delta_{i}^{\prime}}}^{2}}}},} & {{Eq}.(2)} \end{matrix}$

where δ_(i)′ is the uniformly-weighted differential of the input mesh (i.e., initial 3D model 165). When the input mesh is a poor approximation, e.g., a sphere, an absolute regularizer may be used, with δ_(i)′=0. In an embodiment, the combined objective function is:

L _(opt) =L _(image)+λ_(t) L _(δ)  Eq (3)

where λ_(t) is the regularization weight that depends on the current optimization iteration t. λ_(t) may be gradually reduced during optimization according to λ_(t)=(λ_(t-1)−λ_(min))·10^(−kt)+λ_(min). In an embodiment, k=10⁻⁶, and λ_(min) is chosen as 2% of the initial weight, λ₀. The uniform Laplacian regularizer depends on tessellation, whereas the image-domain loss does not. Hence, the image space loss should be balanced against the Laplacian loss when the meshes have greatly varying primitive counts. The initial weight, λ₀, can either be specified by the user or by a simple heuristic. For example, the Laplacian error may be evaluated at the start of optimization, and set as λ₀=0.25 L_(image)/L_(δ).

In non-linear optimization, good initial guesses may have a dramatic effect on the speed of convergence and eventual quality of the resulting reduced resolution 3D model 170. When a high-resolution mesh of the reference 3D model 175 is available, mesh decimation tools may be used to produce the initial 3D model 165. In some cases, e.g., when baking foliage as billboard clouds (as shown in FIG. 2D), prior domain knowledge may be used to explicitly specify a suitable initial mesh. However, starting from a tessellated sphere, as shown in FIGS. 1A and 1C, often yields surprisingly good results. Similarly, if available, texture maps from a reference scene or the reference 3D model 175 may be used as an initial guess for material parameters. In an embodiment, randomly initialized texture maps are used for the initial 3D model 165.

The appearance driven automatic 3D modeling system 150 may be used for many purposes, including, but not limited to joint simplification of shape and appearance, pre-filtering shape and appearance to reduce aliasing, geometric simplification of skinned character animation, approximation of aggregate geometry, and 3D mesh extraction from implicit surfaces. Simplifying complex reference 3D models (e.g., assets) with minimal loss in visual fidelity is a straightforward application. As further described in conjunction with FIGS. 2A, 2B, and 2C, three variants of model simplification demonstrate joint optimization over different combinations of shape and appearance: normal map baking, joint simplification that also accounts for surface reflectance, and approximating complex meshes with displacement maps applied on a coarse base domain.

As an initial example, the initial 3D model 105 may comprise a sphere with 3 k triangles and the shape and a tangent-space normal map may be optimized to produce the reduced resolution 3D model 110 shown in FIG. 1A that approximates a highly detailed reference mesh with 735 k triangles. Besides the normal vectors, the material for the reduced resolution 3D model 110 is otherwise fixed as diffuse uniform gray. While some high-frequency detail is missing from the skull in the rendered 3D model representation 115, the result is nonetheless encouraging, considering that the optimization process may be entirely automatic and uses no direct information about the reference model.

In addition to normal maps, displacement mapping is an increasingly popular technique for representing complex shapes in real-time settings. Displacement mapping achieves a compact representation by tessellating a coarse base mesh on-the-fly and displacing the resulting vertices in the direction of the interpolated surface normal vector by amounts read from a displacement map texture. The appearance driven automatic 3D modeling system 150 enables the use of displacement maps for approximating geometry by simply implementing the tessellation and displacement steps in the forward processing performed by the rendering pipeline 100.

FIG. 2A illustrates a conceptual diagram of normal vector and displacement mapping for a 3D model, in accordance with an embodiment. In an embodiment, the appearance driven automatic 3D modeling system 150 jointly optimizes a base mesh, displacement map, and normal map of an initial 3D model 205 to match the appearance of a 370 k triangle reference 3D model 225 of a dancer. The dancer model is courtesy of the Smithsonian® 3D Digitization project. The 1 k triangle initial 3D model 205 is a decimated mesh generated from the reference 3D model 225. The dancer model presents a complex optimization problem, and the initial 3D model 205 provides a coarsely tessellated base mesh with displacement constrained to the normal direction. Still, the appearance of both a 64 k triangle reduced resolution 3D model 210 comprising a displacement map without a normal map and a 64 k triangle reduced resolution 3D model 215 comprising a displacement map with a normal map, closely match the reference 3D model 225. Interestingly, some small details in an inset 227 portion of the reference 3D model 225 are baked into the normal map of the reduced resolution 3D model 215, even though the small details could be easily represented by displacement. A portion of the rendered initial 3D model 205 corresponding to the inset 227 is shown in 220. A portion of the reduced resolution 3D model 210 (displacement without normals) corresponding to the inset 227 is shown in 222. A portion of the reduced resolution 3D model 215 (displacement with normals) corresponding to the inset 227 is shown in 224.

The reduced resolution 3D model 215 is obtained by jointly optimizing the pre-tessellation shape of the initial 3D model 205, the normal map, and the displacement map. The optimization yields a natural “division of labor” between the representations: the initial 3D model 205 is a base mesh that models the overall shape, the displacement map models mid-scale detail, and the finest detail that is not representable by the displaced surface is captured by the normal map. While the reduced resolution 3D models 210 and 215 shown in FIG. 2A are generated for a single, fixed tessellation level, dynamic tessellation may be used for level-of-detail selection. Additionally, a displacement mapped mesh may be optimized to look good under multiple levels of tessellation.

Much of the difficulty in appearance capture originates from the desire to limit the acquisition effort for the user. Exhaustively measuring real-world appearance under all lighting and view directions is prohibitively expensive for most purposes. In contrast, the reference 3D model 225 can be rendered in as many viewing and lighting conditions as needed to generate the reduced resolution 3D models 210 and 215. The computational complexity is therefore reduced, and direct end-to-end optimization over the material parameters and vertex positions is possible using the visual similarity loss. In an embodiment, the appearance driven automatic 3D modeling system 150 generates the reduced resolution 3D models 210 and 215 comprising triangle meshes and materials that can be rendered in real-time by a standard 3D engine.

Appearance capture can be framed as seeking a digital asset (e.g., a spatially-varying BRDF map and a mesh) whose renderings visually match some real-world object. Appearance capture is conceptually similar to appearance driven automatic 3D modeling, with the exception that for appearance driven automatic 3D modeling the reference 3D models can be other digital assets.

FIG. 2B illustrates a conceptual diagram of normal vector and new lighting scenario for a 3D model, in accordance with an embodiment. Compared with the dancer reference 3D model 225 in FIG. 1B, a reference 3D model 245 is rendered with a uniform, highly specular gold material. A physically-based shading model with one diffuse lobe and one isotropic specular lobe, as is commonly used in modern game engines, may be implemented by the rendering pipeline 100. Joint shape and appearance simplification may be used to generate a reduced resolution 3D model 240 of the reference 3D model 245. Initial 3D model 235 includes 1 k triangles and the reference 3D model 245 includes 370 k triangles. The reduced resolution 3D model 240 includes 1 k triangles—only 0.3% of the triangles that are included in the reference 3D model 245. The reduced resolution model 240 is rendered in a new lighting scenario demonstrating that the materials learned during optimization generalize to new lighting conditions that were not used during optimization.

In contrast with the reduced resolution 3D model 240 shown in FIG. 2A that comprises a spatially uniform BRDF, the reduced resolution 3D model 240 is endowed with a normal map and a spatially-varying BRDF (SVBRDF). As shown by parameters for the dancer's head: mesh 230, diffuse map 232, specular map 234, and normal vectors 236, geometric detail not present in the reduced resolution 3D model 240 becomes approximated in the various spatially varying material parameters. Shape and appearance may be jointly optimized under random views and point light directions. Even though a single point light is used during optimization, the resulting reduced resolution 3D model 240 generalizes to new lighting conditions. In other words, the resulting reduced resolution 3D model 240 generalizes to different environmental conditions. Because appearance driven automatic 3D modeling optimizes based on visual differences, the silhouette of the reduced resolution 3D model 240 closely matches the true silhouette of the reference 3D model 245, accurate normal vectors are computed, and the shaded appearance of the reference 3D model 240 is captured.

In an embodiment, automatic cleanup of unsuccessful mesh decimation operations performed by other applications may be performed using the appearance driven automatic 3D modeling system 150. For example, artifacts in a decimated mesh of a reference 3D model such as decreased volume, detached geometric elements, incorrect texturing, and self-intersecting geometry may be corrected. The decimated mesh is used an initial 3D model, images of the initial 3D model and reduced resolution 3D model are rendered and compared with rendered images of the reference 3D model to produce a version of the decimated mesh having fewer artifacts compared with the decimated mesh.

As previously described, a goal is to create faithful representations of complex assets (e.g., 3D reference models) with reduced resolution (e.g., triangle counts). A closely related goal is to find efficiently renderable approximations to original assets that require a substantial amount of supersampling, due to their complexity, to produce alias-free images. In the context of the following description, joint pre-filtering of shape and appearance is used to refer to a process of producing such efficiently renderable approximations of reference 3D models. Reduced resolution 3D models produced using joint pre-filtering of shape and appearance have the property that they reproduce, when rendered at only one sample-per-pixel (1 spp), the appearance of assets that require potentially hundreds of samples per pixel for alias-free reproduction. During optimization, a smaller target image resolution is typically specified for the rendered images and the reference images should be rendered with enough supersampling to ensure lack of aliasing. In an embodiment, the shading model used by the rendering pipeline 100 comprises one diffuse lobe and one specular lobe, and the mesh shape and the material parameters are adjusted during optimization so that the rendered images match highly supersampled reference images.

FIG. 2C illustrates a conceptual diagram of appearance pre-filtering for a 3D model, in accordance with an embodiment. Reference 3D models 242 and 252 and reduced resolution 3D models 244 and 254, are rendered using 1spp. For comparison, reference 3D models 246 and 256 are rendered using 256spp. Shape and appearance can be jointly pre-filtered for one or more specific rendering resolutions. The reduced resolution 3D model 244 is optimized for an image resolution of 64×64 pixels based on reference images of the reference 3D model 246. The reduced resolution 3D model 254 is optimized for a resolution of 512×512 pixels based on reference images of the reference 3D model 256. Pre-filtering can be achieved in the appearance driven automatic 3D modeling system 150 by updating the rendering pipeline used for the reference 3D model 160 to render reference images using multiple samples and antialiasing.

The reduced resolution 3D model 244 which is pre-filtered for the lower resolution of 64×64 pixels has, as one would expect, considerably smoother normal vectors compared with the reduced resolution 3D model 254 that account, together with the specular map, for the effect of averaging inherent in supersampling. Similarly, compared with the reduced resolution 3D model 254, the reduced resolution 3D model 244 is geometrically smoothed. When rendered at the intended resolution, the reduced resolution 3D models 244 and 254 match the appearance of the respective reference 3D models 242 and 252 well, with no apparent aliasing. The appearance of the supersampled reference 3D models 245 and 256 rendered at 256spp are achieved by the respective reduced resolution 3D models 244 and 254 even though the reduced resolution 3D models 244 and 254 are rendered using 1spp. Thus, reduced resolution 3D models 244 and 254 may be used to produce images at a fraction of the rendering cost compared with the anti-aliased reference 3D models 246 and 256.

To obtain an appropriate amount of pre-filtering at different rendering resolutions (i.e., rendering distances), it is not sufficient to optimize for one resolution only. For materials, it is easy to optimize for multiple resolutions by treating each mip map level separately using per-mip map level parameters in a set of parameters for the materials. Such resolution-specific material representations may be used by existing trilinear texture lookup mechanisms for automatic interpolate between levels. Even though linear interpolation between material parameters is not generally correct, the optimization process will find a representation that, assuming trilinear texture fetches will be used, matches the reference images as well as possible. For geometry, multiple sets of vertex positions may be stored and at least one particular set of vertex positions may be selected based on distance to mesh, average projected edge length, or a similar heuristic. As with mip-mapping, linear interpolation between levels can be used to eliminate popping artifacts.

The pre-filtering technique has the benefit that no changes are needed for a typical game engine to render the reduced resolution models and there is no runtime overhead. The approach is flexible, as any target surface and material representation of the reference 3D model is treated in a unified manner: only the final visual appearance is observed, and it does not matter what combination of, e.g., mesh shape, displacement, normal, and material parameters produced the rendered images.

When the reference 3D model changes position or shape over time, such as in an animation, an animated and articulated reduced resolution 3D model may be generated. In an embodiment, the parameters may include vertex positions, skinning weights, normal maps, and material properties that vary over time. More precisely, given a high-resolution reference 3D model animated by skeletal subspace deformation (SSD), optimization may be performed over bind-pose vertex positions, normal vectors, SVBRDF, and skinning weights (bone-vertex attachments) of an initial 3D model in an attempt to replicate the appearance of the reference animation. In contrast to simplifying the reference 3D model (e.g., character) in the bind pose (T-pose) only, appearance driven automatic 3D modeling holds promise for being able to negotiate compromises to distribute the error evenly among the frames by adjusting the geometry, skinning weights, and materials appropriately.

Compared with other applications, when SSD is used, transformed vertex positions are blended using the skinning weights, a simple linear operation. In an embodiment, an assumption is made that time-varying bone transformations are known and are therefore treated as constants during optimization. In an embodiment, appearance driven, end-to-end joint optimization of both bone transformations and skinning weights, together with geometry and material parameters is performed by the appearance driven automatic 3D modeling system 150.

In another application, shape and appearance of aggregate geometry included in detailed 3D scenes may be approximated by the appearance driven automatic 3D modeling system 150. Stochastic aggregate geometry, such as foliage, are particularly difficult to simplify: as the overall appearance emerges from the combined effect of many small, disjoint components, techniques such as mesh decimation are ineffective. A conventional simplification technique randomly removes a subset of the geometric elements and alters the remaining elements based on a known scene graph, to preserve the overall appearance of a scene. Instead of stochastically pruning the procedural scene graph as is done by the conventional simplification, appearance driven automatic 3D modeling replaces the complex geometries with textured geometry that is simple (e.g., quads). The simple geometry provides the initial 3D model, and the material parameters, shape, and transparency may be jointly optimized based on visual loss of rendered images.

FIG. 2D illustrates a conceptual diagram of simplification of aggregate geometry for a 3D model, in accordance with an embodiment. Foliage is approximated with low-poly proxy geometry and textures. Reference 3D model geometry that is used to produce rendered reference 3D model 246 comprises complex shapes for the foliage, whereas initial 3D model geometry 242 comprises simple quadrilaterals using just a fraction (3.66%) of the triangle count (256 quads or 512 triangles) compared with the reference 3D model geometry (14 k triangles). As shown in FIG. 2D, the quadrilaterals for the initial 3D model geometry 246 are randomly placed in 3D.

In an embodiment, rendered reduced 3D model 244 is produced by optimizing the initial 3D model geometry 242 and associated parameters, including a learned texture 248, using differentiable operations implemented by the rendering pipeline 100. During optimization, vertex positions of the initial 3D model geometry 242 are adjusted and material values are also adjusted to optimize the learned texture 248. In an embodiment, squared L₂ is used as the objective function by the image space loss unit 120. Compared to rendered reference 3D model geometry 246, the appearance of the scene is accurately approximated by the rendered reduced 3D model 244. In addition to colors, the textures include alpha values that effectively shape the reduced 3D model geometry by making portions of the geometry transparent. In addition to geometry, the reference 3D model also includes spatially varying materials and textures with alpha values.

FIG. 3 illustrates a block diagram of the rendering pipeline 100 shown in FIGS. 1A and 1C suitable for use in implementing some embodiments of the present disclosure. It should be understood that this and other arrangements described herein are set forth only as examples. Other arrangements and elements (e.g., machines, interfaces, functions, orders, groupings of functions, etc.) may be used in addition to or instead of those shown, and some elements may be omitted altogether. Further, many of the elements described herein are functional entities that may be implemented as discrete or distributed components or in conjunction with other components, and in any suitable combination and location. Various functions described herein as being performed by entities may be carried out by hardware, firmware, and/or software. For instance, various functions may be carried out by a processor executing instructions stored in memory. Furthermore, persons of ordinary skill in the art will understand that any system that performs the operations of the rendering pipeline 100 for the appearance driven automatic 3D modeling system 150 is within the scope and spirit of embodiments of the present disclosure.

The rendering pipeline 100 optimizes the reduced resolution 3D model 110. In an embodiment, an initial guess for the reduced resolution 3D model 110, such as the initial 3D model 105 is processed and updated, according to the image space losses 122, to produce the reduced resolution 3D model 110. The reduced resolution 3D model 110 may be iteratively updated according to the image space losses 122.

The rendering pipeline 100 comprises multiple processing units including a tangent space construction unit 300, an animation and skinning unit 310, a displacement mapping unit 320, a differentiable rasterizer 330, and a differed shading unit 340. In other embodiment, one or more of the processing units within the rendering pipeline 100 may be omitted or one or more additional units maybe included. In an embodiment, the rendering pipeline 100 comprises modular, configurable, and programmable processing units to enable easy construction of potentially complex custom rendering pipelines. Each one of the processing units performs differentiable operations. One or more of the processing units performs operations related to the various parameters of the initial and reduced resolution 3D models, such as vertex positions, normal (vector) maps, displacement maps, texture maps, skinning weights, and the like.

To optimize tangent space normal maps on deforming geometry, a tangent frame must be differentiable and dynamically updated to reflect any change in vertex position. In an embodiment, the tangent space construction unit 300 computes smooth vertex normals and derives tangent and bi-tangent vectors from the vertex positions and texture coordinates. Using mesh-derived smooth normals is not necessarily a limitation because creases or other sharp features can be handled by the normal map.

Skinning may be supported by optimizing skinning weights and/or a bone transform matrix of animated meshes. A differentiable skinning operator is computed by the animation and skinning unit 310 according to:

v _(i) ^(s)=Σ_(b∈)

w _(ib) M _(b) v _(i)  Eq. (4)

where

is the set of bones, M_(b) is the bone transform matrix for the current frame, and w_(ib) is the skinning weight of bone b influencing vertex v_(i). Weights are typically stored using a sparse indexed representation, but the full dense skinning operator may be implemented to support any vertex-bone association during optimization.

For displacement mapping, the representation of the initial 3D model 105 is a coarse base mesh and scalar displacement map. The mesh is subdivided, and the displacement map is used to displace the tessellated vertices along the interpolated normal direction. Geometry may be tessellated using edge-midpoint subdivision, where each triangle is split into four new triangles by inserting a new vertex along each edge. In an embodiment, the tessellation operation is made differentiable by selecting a constant tessellation factor and precomputing the topology of the tessellated mesh before optimization. The position of each vertex created by the tessellation is recomputed every iteration to ensure that gradients are propagated correctly.

In an embodiment, the displacement mapping unit 320 displaces each vertex according to

v _(i) ^(d) =v _(i)+tex2d(t _(i))·n _(i),  Eq. (5)

where v_(i) is the original tessellated vertex position, n_(i) is the interpolated normal, tex2d is a texture lookup operation, and t_(i) is the texture coordinate. Each of the tangent space construction unit 300, animation and skinning unit 310, and displacement mapping unit 320 operates on a mesh defined by vertices.

The differentiable rasterizer 330 converts the mesh geometry and parameters into attributes for interpolation and the deferred shading unit 340 computes a final color for each pixel of images 122 by performing interpolation, texture lookup, and/or antialiasing operations.

The rendering pipeline 100 receives image space losses 122 that, in an embodiment, indicate how the color of each pixel of the images 122 affects the loss. In an embodiment, backwards propagation through each processing unit in the rendering pipeline 100 computes gradients that are output to the upstream processing unit. When propagating the gradients backwards through the rendering pipeline 100, the gradient of the output for each computation step is known (i.e., how changes in the output values of each computation step will affect the loss), so that the gradients of the inputs to the computation step may be determined (i.e., how changes in the input values of each computation step will affect the loss).

After the image space losses 122 are propagated backwards through the entire rendering pipeline 100, it is possible to quantify how changing the initial 3D model 105 and the reduced resolution 3D model 110 affects the image space losses 122, and the parameters can be adjusted in the direction that should reduce the image space losses 122. The gradients that are computed during backpropagation indicate the effect that moving the vertex positions and adjusting other parameters has on the images 112. The rendering pipeline 100 provides updates and adjusts the reduced resolution 3D model 110 to reduce the image space losses 122.

The appearance driven automatic 3D modeling system 150 enables optimization of a 3D model comprising the shape and appearance of a particular 3D scene or object for individual frames or an animation. Compared with a reference 3D model, the optimized (reduced resolution) 3D model is a lower resolution 3D model that can be rendered in less time. More specifically, the optimized 3D model may include fewer geometric primitives compared with the reference 3D model. The optimized 3D model may be used to improve the performance of a game or other real-time application that is limited by rendering speed. Optimization of the 3D model may be used to perform shape and appearance pre-filtering to improve image quality. More specifically, joint pre-filtering of shape and appearance may be used to produce alias-free images, even when rendering using only one sample per pixel. The appearance driven automatic 3D modeling system 150 may also be used to convert between different model representations. Real-time and/or production rendering applications (e.g., feature film, architectural visualization, etc.) may benefit from the improved image quality.

Parallel Processing Architecture

FIG. 4 illustrates a parallel processing unit (PPU) 400, in accordance with an embodiment. The PPU 400 may be used to implement the appearance driven automatic 3D modeling system 150. The PPU 400 may be used to implement one or more of the rendering pipeline 100, image space loss unit 120, or rendering pipeline 160. In an embodiment, a processor such as the PPU 400 may be configured to implement a neural network model. The neural network model may be implemented as software instructions executed by the processor or, in other embodiments, the processor can include a matrix of hardware elements configured to process a set of inputs (e.g., electrical signals representing values) to generate a set of outputs, which can represent activations of the neural network model. In yet other embodiments, the neural network model can be implemented as a combination of software instructions and processing performed by a matrix of hardware elements. Implementing the neural network model can include determining a set of parameters for the neural network model through, e.g., supervised or unsupervised training of the neural network model as well as, or in the alternative, performing inference using the set of parameters to process novel sets of inputs.

In an embodiment, the PPU 400 is a multi-threaded processor that is implemented on one or more integrated circuit devices. The PPU 400 is a latency hiding architecture designed to process many threads in parallel. A thread (e.g., a thread of execution) is an instantiation of a set of instructions configured to be executed by the PPU 400. In an embodiment, the PPU 400 is a graphics processing unit (GPU) configured to implement a graphics rendering pipeline for processing three-dimensional (3D) graphics data in order to generate two-dimensional (2D) image data for display on a display device. In other embodiments, the PPU 400 may be utilized for performing general-purpose computations. While one exemplary parallel processor is provided herein for illustrative purposes, it should be strongly noted that such processor is set forth for illustrative purposes only, and that any processor may be employed to supplement and/or substitute for the same.

One or more PPUs 400 may be configured to accelerate thousands of High Performance Computing (HPC), data center, cloud computing, and machine learning applications. The PPU 400 may be configured to accelerate numerous deep learning systems and applications for autonomous vehicles, simulation, computational graphics such as ray or path tracing, deep learning, high-accuracy speech, image, and text recognition systems, intelligent video analytics, molecular simulations, drug discovery, disease diagnosis, weather forecasting, big data analytics, astronomy, molecular dynamics simulation, financial modeling, robotics, factory automation, real-time language translation, online search optimizations, and personalized user recommendations, and the like.

As shown in FIG. 4 , the PPU 400 includes an Input/Output (I/O) unit 405, a front end unit 415, a scheduler unit 420, a work distribution unit 425, a hub 430, a crossbar (Xbar) 470, one or more general processing clusters (GPCs) 450, and one or more memory partition units 480. The PPU 400 may be connected to a host processor or other PPUs 400 via one or more high-speed NVLink 410 interconnect. The PPU 400 may be connected to a host processor or other peripheral devices via an interconnect 402. The PPU 400 may also be connected to a local memory 404 comprising a number of memory devices. In an embodiment, the local memory may comprise a number of dynamic random access memory (DRAM) devices. The DRAM devices may be configured as a high-bandwidth memory (HBM) subsystem, with multiple DRAM dies stacked within each device.

The NVLink 410 interconnect enables systems to scale and include one or more PPUs 400 combined with one or more CPUs, supports cache coherence between the PPUs 400 and CPUs, and CPU mastering. Data and/or commands may be transmitted by the NVLink 410 through the hub 430 to/from other units of the PPU 400 such as one or more copy engines, a video encoder, a video decoder, a power management unit, etc. (not explicitly shown). The NVLink 410 is described in more detail in conjunction with FIG. 5B.

The I/O unit 405 is configured to transmit and receive communications (e.g., commands, data, etc.) from a host processor (not shown) over the interconnect 402. The I/O unit 405 may communicate with the host processor directly via the interconnect 402 or through one or more intermediate devices such as a memory bridge. In an embodiment, the I/O unit 405 may communicate with one or more other processors, such as one or more the PPUs 400 via the interconnect 402. In an embodiment, the I/O unit 405 implements a Peripheral Component Interconnect Express (PCIe) interface for communications over a PCIe bus and the interconnect 402 is a PCIe bus. In alternative embodiments, the I/O unit 405 may implement other types of well-known interfaces for communicating with external devices.

The I/O unit 405 decodes packets received via the interconnect 402. In an embodiment, the packets represent commands configured to cause the PPU 400 to perform various operations. The I/O unit 405 transmits the decoded commands to various other units of the PPU 400 as the commands may specify. For example, some commands may be transmitted to the front end unit 415. Other commands may be transmitted to the hub 430 or other units of the PPU 400 such as one or more copy engines, a video encoder, a video decoder, a power management unit, etc. (not explicitly shown). In other words, the I/O unit 405 is configured to route communications between and among the various logical units of the PPU 400.

In an embodiment, a program executed by the host processor encodes a command stream in a buffer that provides workloads to the PPU 400 for processing. A workload may comprise several instructions and data to be processed by those instructions. The buffer is a region in a memory that is accessible (e.g., read/write) by both the host processor and the PPU 400. For example, the I/O unit 405 may be configured to access the buffer in a system memory connected to the interconnect 402 via memory requests transmitted over the interconnect 402. In an embodiment, the host processor writes the command stream to the buffer and then transmits a pointer to the start of the command stream to the PPU 400. The front end unit 415 receives pointers to one or more command streams. The front end unit 415 manages the one or more streams, reading commands from the streams and forwarding commands to the various units of the PPU 400.

The front end unit 415 is coupled to a scheduler unit 420 that configures the various GPCs 450 to process tasks defined by the one or more streams. The scheduler unit 420 is configured to track state information related to the various tasks managed by the scheduler unit 420. The state may indicate which GPC 450 a task is assigned to, whether the task is active or inactive, a priority level associated with the task, and so forth. The scheduler unit 420 manages the execution of a plurality of tasks on the one or more GPCs 450.

The scheduler unit 420 is coupled to a work distribution unit 425 that is configured to dispatch tasks for execution on the GPCs 450. The work distribution unit 425 may track a number of scheduled tasks received from the scheduler unit 420. In an embodiment, the work distribution unit 425 manages a pending task pool and an active task pool for each of the GPCs 450. As a GPC 450 finishes the execution of a task, that task is evicted from the active task pool for the GPC 450 and one of the other tasks from the pending task pool is selected and scheduled for execution on the GPC 450. If an active task has been idle on the GPC 450, such as while waiting for a data dependency to be resolved, then the active task may be evicted from the GPC 450 and returned to the pending task pool while another task in the pending task pool is selected and scheduled for execution on the GPC 450.

In an embodiment, a host processor executes a driver kernel that implements an application programming interface (API) that enables one or more applications executing on the host processor to schedule operations for execution on the PPU 400. In an embodiment, multiple compute applications are simultaneously executed by the PPU 400 and the PPU 400 provides isolation, quality of service (QoS), and independent address spaces for the multiple compute applications. An application may generate instructions (e.g., API calls) that cause the driver kernel to generate one or more tasks for execution by the PPU 400. The driver kernel outputs tasks to one or more streams being processed by the PPU 400. Each task may comprise one or more groups of related threads, referred to herein as a warp. In an embodiment, a warp comprises 32 related threads that may be executed in parallel. Cooperating threads may refer to a plurality of threads including instructions to perform the task and that may exchange data through shared memory. The tasks may be allocated to one or more processing units within a GPC 450 and instructions are scheduled for execution by at least one warp.

The work distribution unit 425 communicates with the one or more GPCs 450 via XBar 470. The XBar 470 is an interconnect network that couples many of the units of the PPU 400 to other units of the PPU 400. For example, the XBar 470 may be configured to couple the work distribution unit 425 to a particular GPC 450. Although not shown explicitly, one or more other units of the PPU 400 may also be connected to the XBar 470 via the hub 430.

The tasks are managed by the scheduler unit 420 and dispatched to a GPC 450 by the work distribution unit 425. The GPC 450 is configured to process the task and generate results. The results may be consumed by other tasks within the GPC 450, routed to a different GPC 450 via the XBar 470, or stored in the memory 404. The results can be written to the memory 404 via the memory partition units 480, which implement a memory interface for reading and writing data to/from the memory 404. The results can be transmitted to another PPU 400 or CPU via the NVLink 410. In an embodiment, the PPU 400 includes a number U of memory partition units 480 that is equal to the number of separate and distinct memory devices of the memory 404 coupled to the PPU 400. Each GPC 450 may include a memory management unit to provide translation of virtual addresses into physical addresses, memory protection, and arbitration of memory requests. In an embodiment, the memory management unit provides one or more translation lookaside buffers (TLBs) for performing translation of virtual addresses into physical addresses in the memory 404.

In an embodiment, the memory partition unit 480 includes a Raster Operations (ROP) unit, a level two (L2) cache, and a memory interface that is coupled to the memory 404. The memory interface may implement 32, 64, 128, 1024-bit data buses, or the like, for high-speed data transfer. The PPU 400 may be connected to up to Y memory devices, such as high bandwidth memory stacks or graphics double-data-rate, version 5, synchronous dynamic random access memory, or other types of persistent storage. In an embodiment, the memory interface implements an HBM2 memory interface and Y equals half U. In an embodiment, the HBM2 memory stacks are located on the same physical package as the PPU 400, providing substantial power and area savings compared with conventional GDDR5 SDRAM systems. In an embodiment, each HBM2 stack includes four memory dies and Y equals 4, with each HBM2 stack including two 128-bit channels per die for a total of 8 channels and a data bus width of 1024 bits.

In an embodiment, the memory 404 supports Single-Error Correcting Double-Error Detecting (SECDED) Error Correction Code (ECC) to protect data. ECC provides higher reliability for compute applications that are sensitive to data corruption. Reliability is especially important in large-scale cluster computing environments where PPUs 400 process very large datasets and/or run applications for extended periods.

In an embodiment, the PPU 400 implements a multi-level memory hierarchy. In an embodiment, the memory partition unit 480 supports a unified memory to provide a single unified virtual address space for CPU and PPU 400 memory, enabling data sharing between virtual memory systems. In an embodiment the frequency of accesses by a PPU 400 to memory located on other processors is traced to ensure that memory pages are moved to the physical memory of the PPU 400 that is accessing the pages more frequently. In an embodiment, the NVLink 410 supports address translation services allowing the PPU 400 to directly access a CPU's page tables and providing full access to CPU memory by the PPU 400.

In an embodiment, copy engines transfer data between multiple PPUs 400 or between PPUs 400 and CPUs. The copy engines can generate page faults for addresses that are not mapped into the page tables. The memory partition unit 480 can then service the page faults, mapping the addresses into the page table, after which the copy engine can perform the transfer. In a conventional system, memory is pinned (e.g., non-pageable) for multiple copy engine operations between multiple processors, substantially reducing the available memory. With hardware page faulting, addresses can be passed to the copy engines without worrying if the memory pages are resident, and the copy process is transparent.

Data from the memory 404 or other system memory may be fetched by the memory partition unit 480 and stored in the L2 cache 460, which is located on-chip and is shared between the various GPCs 450. As shown, each memory partition unit 480 includes a portion of the L2 cache associated with a corresponding memory 404. Lower level caches may then be implemented in various units within the GPCs 450. For example, each of the processing units within a GPC 450 may implement a level one (L1) cache. The L1 cache is private memory that is dedicated to a particular processing unit. The L2 cache 460 is coupled to the memory interface 470 and the XBar 470 and data from the L2 cache may be fetched and stored in each of the L1 caches for processing.

In an embodiment, the processing units within each GPC 450 implement a SIMD (Single-Instruction, Multiple-Data) architecture where each thread in a group of threads (e.g., a warp) is configured to process a different set of data based on the same set of instructions. All threads in the group of threads execute the same instructions. In another embodiment, the processing unit implements a SIMT (Single-Instruction, Multiple Thread) architecture where each thread in a group of threads is configured to process a different set of data based on the same set of instructions, but where individual threads in the group of threads are allowed to diverge during execution. In an embodiment, a program counter, call stack, and execution state is maintained for each warp, enabling concurrency between warps and serial execution within warps when threads within the warp diverge. In another embodiment, a program counter, call stack, and execution state is maintained for each individual thread, enabling equal concurrency between all threads, within and between warps. When execution state is maintained for each individual thread, threads executing the same instructions may be converged and executed in parallel for maximum efficiency.

Cooperative Groups is a programming model for organizing groups of communicating threads that allows developers to express the granularity at which threads are communicating, enabling the expression of richer, more efficient parallel decompositions. Cooperative launch APIs support synchronization amongst thread blocks for the execution of parallel algorithms. Conventional programming models provide a single, simple construct for synchronizing cooperating threads: a barrier across all threads of a thread block (e.g., the syncthreads( ) function). However, programmers would often like to define groups of threads at smaller than thread block granularities and synchronize within the defined groups to enable greater performance, design flexibility, and software reuse in the form of collective group-wide function interfaces.

Cooperative Groups enables programmers to define groups of threads explicitly at sub-block (e.g., as small as a single thread) and multi-block granularities, and to perform collective operations such as synchronization on the threads in a cooperative group. The programming model supports clean composition across software boundaries, so that libraries and utility functions can synchronize safely within their local context without having to make assumptions about convergence. Cooperative Groups primitives enable new patterns of cooperative parallelism, including producer-consumer parallelism, opportunistic parallelism, and global synchronization across an entire grid of thread blocks.

Each processing unit includes a large number (e.g., 128, etc.) of distinct processing cores (e.g., functional units) that may be fully-pipelined, single-precision, double-precision, and/or mixed precision and include a floating point arithmetic logic unit and an integer arithmetic logic unit. In an embodiment, the floating point arithmetic logic units implement the IEEE 754-2008 standard for floating point arithmetic. In an embodiment, the cores include 64 single-precision (32-bit) floating point cores, 64 integer cores, 32 double-precision (64-bit) floating point cores, and 8 tensor cores.

Tensor cores configured to perform matrix operations. In particular, the tensor cores are configured to perform deep learning matrix arithmetic, such as GEMM (matrix-matrix multiplication) for convolution operations during neural network training and inferencing. In an embodiment, each tensor core operates on a 4×4 matrix and performs a matrix multiply and accumulate operation D=A×B+C, where A, B, C, and D are 4×4 matrices.

In an embodiment, the matrix multiply inputs A and B may be integer, fixed-point, or floating point matrices, while the accumulation matrices C and D may be integer, fixed-point, or floating point matrices of equal or higher bitwidths. In an embodiment, tensor cores operate on one, four, or eight bit integer input data with 32-bit integer accumulation. The 8-bit integer matrix multiply requires 1024 operations and results in a full precision product that is then accumulated using 32-bit integer addition with the other intermediate products for a 8×8×16 matrix multiply. In an embodiment, tensor Cores operate on 16-bit floating point input data with 32-bit floating point accumulation. The 16-bit floating point multiply requires 64 operations and results in a full precision product that is then accumulated using 32-bit floating point addition with the other intermediate products for a 4×4×4 matrix multiply. In practice, Tensor Cores are used to perform much larger two-dimensional or higher dimensional matrix operations, built up from these smaller elements. An API, such as CUDA 9 C++ API, exposes specialized matrix load, matrix multiply and accumulate, and matrix store operations to efficiently use Tensor Cores from a CUDA-C++ program. At the CUDA level, the warp-level interface assumes 16×16 size matrices spanning all 32 threads of the warp.

Each processing unit may also comprise M special function units (SFUs) that perform special functions (e.g., attribute evaluation, reciprocal square root, and the like). In an embodiment, the SFUs may include a tree traversal unit configured to traverse a hierarchical tree data structure. In an embodiment, the SFUs may include texture unit configured to perform texture map filtering operations. In an embodiment, the texture units are configured to load texture maps (e.g., a 2D array of texels) from the memory 404 and sample the texture maps to produce sampled texture values for use in shader programs executed by the processing unit. In an embodiment, the texture maps are stored in shared memory that may comprise or include an L1 cache. The texture units implement texture operations such as filtering operations using mip-maps (e.g., texture maps of varying levels of detail). In an embodiment, each processing unit includes two texture units.

Each processing unit also comprises N load store units (LSUs) that implement load and store operations between the shared memory and the register file. Each processing unit includes an interconnect network that connects each of the cores to the register file and the LSU to the register file, shared memory. In an embodiment, the interconnect network is a crossbar that can be configured to connect any of the cores to any of the registers in the register file and connect the LSUs to the register file and memory locations in shared memory.

The shared memory is an array of on-chip memory that allows for data storage and communication between the processing units and between threads within a processing unit. In an embodiment, the shared memory comprises 128 KB of storage capacity and is in the path from each of the processing units to the memory partition unit 480. The shared memory can be used to cache reads and writes. One or more of the shared memory, L1 cache, L2 cache, and memory 404 are backing stores.

Combining data cache and shared memory functionality into a single memory block provides the best overall performance for both types of memory accesses. The capacity is usable as a cache by programs that do not use shared memory. For example, if shared memory is configured to use half of the capacity, texture and load/store operations can use the remaining capacity. Integration within the shared memory enables the shared memory to function as a high-throughput conduit for streaming data while simultaneously providing high-bandwidth and low-latency access to frequently reused data.

When configured for general purpose parallel computation, a simpler configuration can be used compared with graphics processing. Specifically, fixed function graphics processing units, are bypassed, creating a much simpler programming model. In the general purpose parallel computation configuration, the work distribution unit 425 assigns and distributes blocks of threads directly to the processing units within the GPCs 450. Threads execute the same program, using a unique thread ID in the calculation to ensure each thread generates unique results, using the processing unit(s) to execute the program and perform calculations, shared memory to communicate between threads, and the LSU to read and write global memory through the shared memory and the memory partition unit 480. When configured for general purpose parallel computation, the processing units can also write commands that the scheduler unit 420 can use to launch new work on the processing units.

The PPUs 400 may each include, and/or be configured to perform functions of, one or more processing cores and/or components thereof, such as Tensor Cores (TCs), Tensor Processing Units (TPUs), Pixel Visual Cores (PVCs), Ray Tracing (RT) Cores, Vision Processing Units (VPUs), Graphics Processing Clusters (GPCs), Texture Processing Clusters (TPCs), Streaming Multiprocessors (SMs), Tree Traversal Units (TTUs), Artificial Intelligence Accelerators (AIAs), Deep Learning Accelerators (DLAs), Arithmetic-Logic Units (ALUs), Application-Specific Integrated Circuits (ASICs), Floating Point Units (FPUs), input/output (I/O) elements, peripheral component interconnect (PCI) or peripheral component interconnect express (PCIe) elements, and/or the like.

The PPU 400 may be included in a desktop computer, a laptop computer, a tablet computer, servers, supercomputers, a smart-phone (e.g., a wireless, hand-held device), personal digital assistant (PDA), a digital camera, a vehicle, a head mounted display, a hand-held electronic device, and the like. In an embodiment, the PPU 400 is embodied on a single semiconductor substrate. In another embodiment, the PPU 400 is included in a system-on-a-chip (SoC) along with one or more other devices such as additional PPUs 400, the memory 404, a reduced instruction set computer (RISC) CPU, a memory management unit (MMU), a digital-to-analog converter (DAC), and the like.

In an embodiment, the PPU 400 may be included on a graphics card that includes one or more memory devices. The graphics card may be configured to interface with a PCIe slot on a motherboard of a desktop computer. In yet another embodiment, the PPU 400 may be an integrated graphics processing unit (iGPU) or parallel processor included in the chipset of the motherboard. In yet another embodiment, the PPU 400 may be realized in reconfigurable hardware. In yet another embodiment, parts of the PPU 400 may be realized in reconfigurable hardware.

Exemplary Computing System

Systems with multiple GPUs and CPUs are used in a variety of industries as developers expose and leverage more parallelism in applications such as artificial intelligence computing. High-performance GPU-accelerated systems with tens to many thousands of compute nodes are deployed in data centers, research facilities, and supercomputers to solve ever larger problems. As the number of processing devices within the high-performance systems increases, the communication and data transfer mechanisms need to scale to support the increased bandwidth.

FIG. 5A is a conceptual diagram of a processing system 500 implemented using the PPU 400 of FIG. 4 , in accordance with an embodiment. The exemplary system 565 may be configured to implement the appearance driven automatic 3D modeling system 150 and/or the method 130 shown in FIG. 1B. The processing system 500 includes a CPU 530, switch 510, and multiple PPUs 400, and respective memories 404.

The NVLink 410 provides high-speed communication links between each of the PPUs 400. Although a particular number of NVLink 410 and interconnect 402 connections are illustrated in FIG. 5B, the number of connections to each PPU 400 and the CPU 530 may vary. The switch 510 interfaces between the interconnect 402 and the CPU 530. The PPUs 400, memories 404, and NVLinks 410 may be situated on a single semiconductor platform to form a parallel processing module 525. In an embodiment, the switch 510 supports two or more protocols to interface between various different connections and/or links.

In another embodiment (not shown), the NVLink 410 provides one or more high-speed communication links between each of the PPUs 400 and the CPU 530 and the switch 510 interfaces between the interconnect 402 and each of the PPUs 400. The PPUs 400, memories 404, and interconnect 402 may be situated on a single semiconductor platform to form a parallel processing module 525. In yet another embodiment (not shown), the interconnect 402 provides one or more communication links between each of the PPUs 400 and the CPU 530 and the switch 510 interfaces between each of the PPUs 400 using the NVLink 410 to provide one or more high-speed communication links between the PPUs 400. In another embodiment (not shown), the NVLink 410 provides one or more high-speed communication links between the PPUs 400 and the CPU 530 through the switch 510. In yet another embodiment (not shown), the interconnect 402 provides one or more communication links between each of the PPUs 400 directly. One or more of the NVLink 410 high-speed communication links may be implemented as a physical NVLink interconnect or either an on-chip or on-die interconnect using the same protocol as the NVLink 410.

In the context of the present description, a single semiconductor platform may refer to a sole unitary semiconductor-based integrated circuit fabricated on a die or chip. It should be noted that the term single semiconductor platform may also refer to multi-chip modules with increased connectivity which simulate on-chip operation and make substantial improvements over utilizing a conventional bus implementation. Of course, the various circuits or devices may also be situated separately or in various combinations of semiconductor platforms per the desires of the user. Alternately, the parallel processing module 525 may be implemented as a circuit board substrate and each of the PPUs 400 and/or memories 404 may be packaged devices. In an embodiment, the CPU 530, switch 510, and the parallel processing module 525 are situated on a single semiconductor platform.

In an embodiment, the signaling rate of each NVLink 410 is 20 to 25 Gigabits/second and each PPU 400 includes six NVLink 410 interfaces (as shown in FIG. 5A, five NVLink 410 interfaces are included for each PPU 400). Each NVLink 410 provides a data transfer rate of 25 Gigabytes/second in each direction, with six links providing 400 Gigabytes/second. The NVLinks 410 can be used exclusively for PPU-to-PPU communication as shown in FIG. 5A, or some combination of PPU-to-PPU and PPU-to-CPU, when the CPU 530 also includes one or more NVLink 410 interfaces.

In an embodiment, the NVLink 410 allows direct load/store/atomic access from the CPU 530 to each PPU's 400 memory 404. In an embodiment, the NVLink 410 supports coherency operations, allowing data read from the memories 404 to be stored in the cache hierarchy of the CPU 530, reducing cache access latency for the CPU 530. In an embodiment, the NVLink 410 includes support for Address Translation Services (ATS), allowing the PPU 400 to directly access page tables within the CPU 530. One or more of the NVLinks 410 may also be configured to operate in a low-power mode.

FIG. 5B illustrates an exemplary system 565 in which the various architecture and/or functionality of the various previous embodiments may be implemented. The exemplary system 565 may be configured to implement the appearance driven automatic 3D modeling system 150 and/or the method 130 shown in FIG. 1B.

As shown, a system 565 is provided including at least one central processing unit 530 that is connected to a communication bus 575. The communication bus 575 may directly or indirectly couple one or more of the following devices: main memory 540, network interface 535, CPU(s) 530, display device(s) 545, input device(s) 560, switch 510, and parallel processing system 525. The communication bus 575 may be implemented using any suitable protocol and may represent one or more links or busses, such as an address bus, a data bus, a control bus, or a combination thereof. The communication bus 575 may include one or more bus or link types, such as an industry standard architecture (ISA) bus, an extended industry standard architecture (EISA) bus, a video electronics standards association (VESA) bus, a peripheral component interconnect (PCI) bus, a peripheral component interconnect express (PCIe) bus, HyperTransport, and/or another type of bus or link. In some embodiments, there are direct connections between components. As an example, the CPU(s) 530 may be directly connected to the main memory 540. Further, the CPU(s) 530 may be directly connected to the parallel processing system 525. Where there is direct, or point-to-point connection between components, the communication bus 575 may include a PCIe link to carry out the connection. In these examples, a PCI bus need not be included in the system 565.

Although the various blocks of FIG. 5C are shown as connected via the communication bus 575 with lines, this is not intended to be limiting and is for clarity only. For example, in some embodiments, a presentation component, such as display device(s) 545, may be considered an I/O component, such as input device(s) 560 (e.g., if the display is a touch screen). As another example, the CPU(s) 530 and/or parallel processing system 525 may include memory (e.g., the main memory 540 may be representative of a storage device in addition to the parallel processing system 525, the CPUs 530, and/or other components). In other words, the computing device of FIG. 5C is merely illustrative. Distinction is not made between such categories as “workstation,” “server,” “laptop,” “desktop,” “tablet,” “client device,” “mobile device,” “hand-held device,” “game console,” “electronic control unit (ECU),” “virtual reality system,” and/or other device or system types, as all are contemplated within the scope of the computing device of FIG. 5C.

The system 565 also includes a main memory 540. Control logic (software) and data are stored in the main memory 540 which may take the form of a variety of computer-readable media. The computer-readable media may be any available media that may be accessed by the system 565. The computer-readable media may include both volatile and nonvolatile media, and removable and non-removable media. By way of example, and not limitation, the computer-readable media may comprise computer-storage media and communication media.

The computer-storage media may include both volatile and nonvolatile media and/or removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules, and/or other data types. For example, the main memory 540 may store computer-readable instructions (e.g., that represent a program(s) and/or a program element(s), such as an operating system. Computer-storage media may include, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which may be used to store the desired information and which may be accessed by system 565. As used herein, computer storage media does not comprise signals per se.

The computer storage media may embody computer-readable instructions, data structures, program modules, and/or other data types in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term “modulated data signal” may refer to a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, the computer storage media may include wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared and other wireless media. Combinations of any of the above should also be included within the scope of computer-readable media.

Computer programs, when executed, enable the system 565 to perform various functions. The CPU(s) 530 may be configured to execute at least some of the computer-readable instructions to control one or more components of the system 565 to perform one or more of the methods and/or processes described herein. The CPU(s) 530 may each include one or more cores (e.g., one, two, four, eight, twenty-eight, seventy-two, etc.) that are capable of handling a multitude of software threads simultaneously. The CPU(s) 530 may include any type of processor, and may include different types of processors depending on the type of system 565 implemented (e.g., processors with fewer cores for mobile devices and processors with more cores for servers). For example, depending on the type of system 565, the processor may be an Advanced RISC Machines (ARM) processor implemented using Reduced Instruction Set Computing (RISC) or an x86 processor implemented using Complex Instruction Set Computing (CISC). The system 565 may include one or more CPUs 530 in addition to one or more microprocessors or supplementary co-processors, such as math co-processors.

In addition to or alternatively from the CPU(s) 530, the parallel processing module 525 may be configured to execute at least some of the computer-readable instructions to control one or more components of the system 565 to perform one or more of the methods and/or processes described herein. The parallel processing module 525 may be used by the system 565 to render graphics (e.g., 3D graphics) or perform general purpose computations. For example, the parallel processing module 525 may be used for General-Purpose computing on GPUs (GPGPU). In embodiments, the CPU(s) 530 and/or the parallel processing module 525 may discretely or jointly perform any combination of the methods, processes and/or portions thereof.

The system 565 also includes input device(s) 560, the parallel processing system 525, and display device(s) 545. The display device(s) 545 may include a display (e.g., a monitor, a touch screen, a television screen, a heads-up-display (HUD), other display types, or a combination thereof), speakers, and/or other presentation components. The display device(s) 545 may receive data from other components (e.g., the parallel processing system 525, the CPU(s) 530, etc.), and output the data (e.g., as an image, video, sound, etc.).

The network interface 535 may enable the system 565 to be logically coupled to other devices including the input devices 560, the display device(s) 545, and/or other components, some of which may be built in to (e.g., integrated in) the system 565. Illustrative input devices 560 include a microphone, mouse, keyboard, joystick, game pad, game controller, satellite dish, scanner, printer, wireless device, etc. The input devices 560 may provide a natural user interface (NUI) that processes air gestures, voice, or other physiological inputs generated by a user. In some instances, inputs may be transmitted to an appropriate network element for further processing. An NUI may implement any combination of speech recognition, stylus recognition, facial recognition, biometric recognition, gesture recognition both on screen and adjacent to the screen, air gestures, head and eye tracking, and touch recognition (as described in more detail below) associated with a display of the system 565. The system 565 may be include depth cameras, such as stereoscopic camera systems, infrared camera systems, RGB camera systems, touchscreen technology, and combinations of these, for gesture detection and recognition. Additionally, the system 565 may include accelerometers or gyroscopes (e.g., as part of an inertia measurement unit (IMU)) that enable detection of motion. In some examples, the output of the accelerometers or gyroscopes may be used by the system 565 to render immersive augmented reality or virtual reality.

Further, the system 565 may be coupled to a network (e.g., a telecommunications network, local area network (LAN), wireless network, wide area network (WAN) such as the Internet, peer-to-peer network, cable network, or the like) through a network interface 535 for communication purposes. The system 565 may be included within a distributed network and/or cloud computing environment.

The network interface 535 may include one or more receivers, transmitters, and/or transceivers that enable the system 565 to communicate with other computing devices via an electronic communication network, included wired and/or wireless communications. The network interface 535 may include components and functionality to enable communication over any of a number of different networks, such as wireless networks (e.g., Wi-Fi, Z-Wave, Bluetooth, Bluetooth LE, ZigBee, etc.), wired networks (e.g., communicating over Ethernet or InfiniBand), low-power wide-area networks (e.g., LoRaWAN, SigFox, etc.), and/or the Internet.

The system 565 may also include a secondary storage (not shown). The secondary storage includes, for example, a hard disk drive and/or a removable storage drive, representing a floppy disk drive, a magnetic tape drive, a compact disk drive, digital versatile disk (DVD) drive, recording device, universal serial bus (USB) flash memory. The removable storage drive reads from and/or writes to a removable storage unit in a well-known manner. The system 565 may also include a hard-wired power supply, a battery power supply, or a combination thereof (not shown). The power supply may provide power to the system 565 to enable the components of the system 565 to operate.

Each of the foregoing modules and/or devices may even be situated on a single semiconductor platform to form the system 565. Alternately, the various modules may also be situated separately or in various combinations of semiconductor platforms per the desires of the user. While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of a preferred embodiment should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Example Network Environments

Network environments suitable for use in implementing embodiments of the disclosure may include one or more client devices, servers, network attached storage (NAS), other backend devices, and/or other device types. The client devices, servers, and/or other device types (e.g., each device) may be implemented on one or more instances of the processing system 500 of FIG. 5A and/or exemplary system 565 of FIG. 5B—e.g., each device may include similar components, features, and/or functionality of the processing system 500 and/or exemplary system 565.

Components of a network environment may communicate with each other via a network(s), which may be wired, wireless, or both. The network may include multiple networks, or a network of networks. By way of example, the network may include one or more Wide Area Networks (WANs), one or more Local Area Networks (LANs), one or more public networks such as the Internet and/or a public switched telephone network (PSTN), and/or one or more private networks. Where the network includes a wireless telecommunications network, components such as a base station, a communications tower, or even access points (as well as other components) may provide wireless connectivity.

Compatible network environments may include one or more peer-to-peer network environments—in which case a server may not be included in a network environment—and one or more client-server network environments—in which case one or more servers may be included in a network environment. In peer-to-peer network environments, functionality described herein with respect to a server(s) may be implemented on any number of client devices.

In at least one embodiment, a network environment may include one or more cloud-based network environments, a distributed computing environment, a combination thereof, etc. A cloud-based network environment may include a framework layer, a job scheduler, a resource manager, and a distributed file system implemented on one or more of servers, which may include one or more core network servers and/or edge servers. A framework layer may include a framework to support software of a software layer and/or one or more application(s) of an application layer. The software or application(s) may respectively include web-based service software or applications. In embodiments, one or more of the client devices may use the web-based service software or applications (e.g., by accessing the service software and/or applications via one or more application programming interfaces (APIs)). The framework layer may be, but is not limited to, a type of free and open-source software web application framework such as that may use a distributed file system for large-scale data processing (e.g., “big data”).

A cloud-based network environment may provide cloud computing and/or cloud storage that carries out any combination of computing and/or data storage functions described herein (or one or more portions thereof). Any of these various functions may be distributed over multiple locations from central or core servers (e.g., of one or more data centers that may be distributed across a state, a region, a country, the globe, etc.). If a connection to a user (e.g., a client device) is relatively close to an edge server(s), a core server(s) may designate at least a portion of the functionality to the edge server(s). A cloud-based network environment may be private (e.g., limited to a single organization), may be public (e.g., available to many organizations), and/or a combination thereof (e.g., a hybrid cloud environment).

The client device(s) may include at least some of the components, features, and functionality of the example processing system 500 of FIG. 5B and/or exemplary system 565 of FIG. 5C. By way of example and not limitation, a client device may be embodied as a Personal Computer (PC), a laptop computer, a mobile device, a smartphone, a tablet computer, a smart watch, a wearable computer, a Personal Digital Assistant (PDA), an MP3 player, a virtual reality headset, a Global Positioning System (GPS) or device, a video player, a video camera, a surveillance device or system, a vehicle, a boat, a flying vessel, a virtual machine, a drone, a robot, a handheld communications device, a hospital device, a gaming device or system, an entertainment system, a vehicle computer system, an embedded system controller, a remote control, an appliance, a consumer electronic device, a workstation, an edge device, any combination of these delineated devices, or any other suitable device.

Machine Learning

Deep neural networks (DNNs) developed on processors, such as the PPU 400 have been used for diverse use cases, from self-driving cars to faster drug development, from automatic image captioning in online image databases to smart real-time language translation in video chat applications. Deep learning is a technique that models the neural learning process of the human brain, continually learning, continually getting smarter, and delivering more accurate results more quickly over time. A child is initially taught by an adult to correctly identify and classify various shapes, eventually being able to identify shapes without any coaching. Similarly, a deep learning or neural learning system needs to be trained in object recognition and classification for it get smarter and more efficient at identifying basic objects, occluded objects, etc., while also assigning context to objects.

At the simplest level, neurons in the human brain look at various inputs that are received, importance levels are assigned to each of these inputs, and output is passed on to other neurons to act upon. An artificial neuron or perceptron is the most basic model of a neural network. In one example, a perceptron may receive one or more inputs that represent various features of an object that the perceptron is being trained to recognize and classify, and each of these features is assigned a certain weight based on the importance of that feature in defining the shape of an object.

A deep neural network (DNN) model includes multiple layers of many connected nodes (e.g., perceptrons, Boltzmann machines, radial basis functions, convolutional layers, etc.) that can be trained with enormous amounts of input data to quickly solve complex problems with high accuracy. In one example, a first layer of the DNN model breaks down an input image of an automobile into various sections and looks for basic patterns such as lines and angles. The second layer assembles the lines to look for higher level patterns such as wheels, windshields, and mirrors. The next layer identifies the type of vehicle, and the final few layers generate a label for the input image, identifying the model of a specific automobile brand.

Once the DNN is trained, the DNN can be deployed and used to identify and classify objects or patterns in a process known as inference. Examples of inference (the process through which a DNN extracts useful information from a given input) include identifying handwritten numbers on checks deposited into ATM machines, identifying images of friends in photos, delivering movie recommendations to over fifty million users, identifying and classifying different types of automobiles, pedestrians, and road hazards in driverless cars, or translating human speech in real-time.

During training, data flows through the DNN in a forward propagation phase until a prediction is produced that indicates a label corresponding to the input. If the neural network does not correctly label the input, then errors between the correct label and the predicted label are analyzed, and the weights are adjusted for each feature during a backward propagation phase until the DNN correctly labels the input and other inputs in a training dataset. Training complex neural networks requires massive amounts of parallel computing performance, including floating-point multiplications and additions that are supported by the PPU 400. Inferencing is less compute-intensive than training, being a latency-sensitive process where a trained neural network is applied to new inputs it has not seen before to classify images, detect emotions, identify recommendations, recognize and translate speech, and generally infer new information.

Neural networks rely heavily on matrix math operations, and complex multi-layered networks require tremendous amounts of floating-point performance and bandwidth for both efficiency and speed. With thousands of processing cores, optimized for matrix math operations, and delivering tens to hundreds of TFLOPS of performance, the PPU 400 is a computing platform capable of delivering performance required for deep neural network-based artificial intelligence and machine learning applications.

Furthermore, images generated applying one or more of the techniques disclosed herein may be used to train, test, or certify DNNs used to recognize objects and environments in the real world. Such images may include scenes of roadways, factories, buildings, urban settings, rural settings, humans, animals, and any other physical object or real-world setting. Such images may be used to train, test, or certify DNNs that are employed in machines or robots to manipulate, handle, or modify physical objects in the real world. Furthermore, such images may be used to train, test, or certify DNNs that are employed in autonomous vehicles to navigate and move the vehicles through the real world. Additionally, images generated applying one or more of the techniques disclosed herein may be used to convey information to users of such machines, robots, and vehicles.

FIG. 5C illustrates components of an exemplary system 555 that can be used to train and utilize machine learning, in accordance with at least one embodiment. As will be discussed, various components can be provided by various combinations of computing devices and resources, or a single computing system, which may be under control of a single entity or multiple entities. Further, aspects may be triggered, initiated, or requested by different entities. In at least one embodiment training of a neural network might be instructed by a provider associated with provider environment 506, while in at least one embodiment training might be requested by a customer or other user having access to a provider environment through a client device 502 or other such resource. In at least one embodiment, training data (or data to be analyzed by a trained neural network) can be provided by a provider, a user, or a third party content provider 524. In at least one embodiment, client device 502 may be a vehicle or object that is to be navigated on behalf of a user, for example, which can submit requests and/or receive instructions that assist in navigation of a device.

In at least one embodiment, requests are able to be submitted across at least one network 504 to be received by a provider environment 506. In at least one embodiment, a client device may be any appropriate electronic and/or computing devices enabling a user to generate and send such requests, such as, but not limited to, desktop computers, notebook computers, computer servers, smartphones, tablet computers, gaming consoles (portable or otherwise), computer processors, computing logic, and set-top boxes. Network(s) 504 can include any appropriate network for transmitting a request or other such data, as may include Internet, an intranet, an Ethernet, a cellular network, a local area network (LAN), a wide area network (WAN), a personal area network (PAN), an ad hoc network of direct wireless connections among peers, and so on.

In at least one embodiment, requests can be received at an interface layer 508, which can forward data to a training and inference manager 532, in this example. The training and inference manager 532 can be a system or service including hardware and software for managing requests and service corresponding data or content, in at least one embodiment, the training and inference manager 532 can receive a request to train a neural network, and can provide data for a request to a training module 512. In at least one embodiment, training module 512 can select an appropriate model or neural network to be used, if not specified by the request, and can train a model using relevant training data. In at least one embodiment, training data can be a batch of data stored in a training data repository 514, received from client device 502, or obtained from a third party provider 524. In at least one embodiment, training module 512 can be responsible for training data. A neural network can be any appropriate network, such as a recurrent neural network (RNN) or convolutional neural network (CNN). Once a neural network is trained and successfully evaluated, a trained neural network can be stored in a model repository 516, for example, that may store different models or networks for users, applications, or services, etc. In at least one embodiment, there may be multiple models for a single application or entity, as may be utilized based on a number of different factors.

In at least one embodiment, at a subsequent point in time, a request may be received from client device 502 (or another such device) for content (e.g., path determinations) or data that is at least partially determined or impacted by a trained neural network. This request can include, for example, input data to be processed using a neural network to obtain one or more inferences or other output values, classifications, or predictions, or for at least one embodiment, input data can be received by interface layer 508 and directed to inference module 518, although a different system or service can be used as well. In at least one embodiment, inference module 518 can obtain an appropriate trained network, such as a trained deep neural network (DNN) as discussed herein, from model repository 516 if not already stored locally to inference module 518. Inference module 518 can provide data as input to a trained network, which can then generate one or more inferences as output. This may include, for example, a classification of an instance of input data. In at least one embodiment, inferences can then be transmitted to client device 502 for display or other communication to a user. In at least one embodiment, context data for a user may also be stored to a user context data repository 522, which may include data about a user which may be useful as input to a network in generating inferences, or determining data to return to a user after obtaining instances. In at least one embodiment, relevant data, which may include at least some of input or inference data, may also be stored to a local database 534 for processing future requests. In at least one embodiment, a user can use account information or other information to access resources or functionality of a provider environment. In at least one embodiment, if permitted and available, user data may also be collected and used to further train models, in order to provide more accurate inferences for future requests. In at least one embodiment, requests may be received through a user interface to a machine learning application 526 executing on client device 502, and results displayed through a same interface. A client device can include resources such as a processor 528 and memory 562 for generating a request and processing results or a response, as well as at least one data storage element 552 for storing data for machine learning application 526.

In at least one embodiment a processor 528 (or a processor of training module 512 or inference module 518) will be a central processing unit (CPU). As mentioned, however, resources in such environments can utilize GPUs to process data for at least certain types of requests. With thousands of cores, GPUs, such as PPU 300 are designed to handle substantial parallel workloads and, therefore, have become popular in deep learning for training neural networks and generating predictions. While use of GPUs for offline builds has enabled faster training of larger and more complex models, generating predictions offline implies that either request-time input features cannot be used or predictions must be generated for all permutations of features and stored in a lookup table to serve real-time requests. If a deep learning framework supports a CPU-mode and a model is small and simple enough to perform a feed-forward on a CPU with a reasonable latency, then a service on a CPU instance could host a model. In this case, training can be done offline on a GPU and inference done in real-time on a CPU. If a CPU approach is not viable, then a service can run on a GPU instance. Because GPUs have different performance and cost characteristics than CPUs, however, running a service that offloads a runtime algorithm to a GPU can require it to be designed differently from a CPU based service.

In at least one embodiment, video data can be provided from client device 502 for enhancement in provider environment 506. In at least one embodiment, video data can be processed for enhancement on client device 502. In at least one embodiment, video data may be streamed from a third party content provider 524 and enhanced by third party content provider 524, provider environment 506, or client device 502. In at least one embodiment, video data can be provided from client device 502 for use as training data in provider environment 506.

In at least one embodiment, supervised and/or unsupervised training can be performed by the client device 502 and/or the provider environment 506. In at least one embodiment, a set of training data 514 (e.g., classified or labeled data) is provided as input to function as training data. In at least one embodiment, training data can include instances of at least one type of object for which a neural network is to be trained, as well as information that identifies that type of object. In at least one embodiment, training data might include a set of images that each includes a representation of a type of object, where each image also includes, or is associated with, a label, metadata, classification, or other piece of information identifying a type of object represented in a respective image. Various other types of data may be used as training data as well, as may include text data, audio data, video data, and so on. In at least one embodiment, training data 514 is provided as training input to a training module 512. In at least one embodiment, training module 512 can be a system or service that includes hardware and software, such as one or more computing devices executing a training application, for training a neural network (or other model or algorithm, etc.). In at least one embodiment, training module 512 receives an instruction or request indicating a type of model to be used for training, in at least one embodiment, a model can be any appropriate statistical model, network, or algorithm useful for such purposes, as may include an artificial neural network, deep learning algorithm, learning classifier, Bayesian network, and so on. In at least one embodiment, training module 512 can select an initial model, or other untrained model, from an appropriate repository 516 and utilize training data 514 to train a model, thereby generating a trained model (e.g., trained deep neural network) that can be used to classify similar types of data, or generate other such inferences. In at least one embodiment where training data is not used, an appropriate initial model can still be selected for training on input data per training module 512.

In at least one embodiment, a model can be trained in a number of different ways, as may depend in part upon a type of model selected. In at least one embodiment, a machine learning algorithm can be provided with a set of training data, where a model is a model artifact created by a training process. In at least one embodiment, each instance of training data contains a correct answer (e.g., classification), which can be referred to as a target or target attribute. In at least one embodiment, a learning algorithm finds patterns in training data that map input data attributes to a target, an answer to be predicted, and a machine learning model is output that captures these patterns. In at least one embodiment, a machine learning model can then be used to obtain predictions on new data for which a target is not specified.

In at least one embodiment, training and inference manager 532 can select from a set of machine learning models including binary classification, multiclass classification, generative, and regression models. In at least one embodiment, a type of model to be used can depend at least in part upon a type of target to be predicted.

Graphics Processing Pipeline

In an embodiment, the PPU 400 comprises a graphics processing unit (GPU). The PPU 400 is configured to receive commands that specify shader programs for processing graphics data. Graphics data may be defined as a set of primitives such as points, lines, triangles, quads, triangle strips, and the like. Typically, a primitive includes data that specifies a number of vertices for the primitive (e.g., in a model-space coordinate system) as well as attributes associated with each vertex of the primitive. The PPU 400 can be configured to process the graphics primitives to generate a frame buffer (e.g., pixel data for each of the pixels of the display).

An application writes model data for a scene (e.g., a collection of vertices and attributes) to a memory such as a system memory or memory 404. The model data defines each of the objects that may be visible on a display. The application then makes an API call to the driver kernel that requests the model data to be rendered and displayed. The driver kernel reads the model data and writes commands to the one or more streams to perform operations to process the model data. The commands may reference different shader programs to be implemented on the processing units within the PPU 400 including one or more of a vertex shader, hull shader, domain shader, geometry shader, and a pixel shader. For example, one or more of the processing units may be configured to execute a vertex shader program that processes a number of vertices defined by the model data. In an embodiment, the different processing units may be configured to execute different shader programs concurrently. For example, a first subset of processing units may be configured to execute a vertex shader program while a second subset of processing units may be configured to execute a pixel shader program. The first subset of processing units processes vertex data to produce processed vertex data and writes the processed vertex data to the L2 cache 460 and/or the memory 404. After the processed vertex data is rasterized (e.g., transformed from three-dimensional data into two-dimensional data in screen space) to produce fragment data, the second subset of processing units executes a pixel shader to produce processed fragment data, which is then blended with other processed fragment data and written to the frame buffer in memory 404. The vertex shader program and pixel shader program may execute concurrently, processing different data from the same scene in a pipelined fashion until all of the model data for the scene has been rendered to the frame buffer. Then, the contents of the frame buffer are transmitted to a display controller for display on a display device.

FIG. 6A is a conceptual diagram of a graphics processing pipeline 600 implemented by the PPU 400 of FIG. 4 , in accordance with an embodiment. The graphics processing pipeline 600 is an abstract flow diagram of the processing steps implemented to generate 2D computer-generated images from 3D geometry data. As is well-known, pipeline architectures may perform long latency operations more efficiently by splitting up the operation into a plurality of stages, where the output of each stage is coupled to the input of the next successive stage. Thus, the graphics processing pipeline 600 receives input data 601 that is transmitted from one stage to the next stage of the graphics processing pipeline 600 to generate output data 602. In an embodiment, the graphics processing pipeline 600 may represent a graphics processing pipeline defined by the OpenGL® API. As an option, the graphics processing pipeline 600 may be implemented in the context of the functionality and architecture of the previous Figures and/or any subsequent Figure(s).

As shown in FIG. 6A, the graphics processing pipeline 600 comprises a pipeline architecture that includes a number of stages. The stages include, but are not limited to, a data assembly stage 610, a vertex shading stage 620, a primitive assembly stage 630, a geometry shading stage 640, a viewport scale, cull, and clip (VSCC) stage 650, a rasterization stage 660, a fragment shading stage 670, and a raster operations stage 680. In an embodiment, the input data 601 comprises commands that configure the processing units to implement the stages of the graphics processing pipeline 600 and geometric primitives (e.g., points, lines, triangles, quads, triangle strips or fans, etc.) to be processed by the stages. The output data 602 may comprise pixel data (e.g., color data) that is copied into a frame buffer or other type of surface data structure in a memory.

The data assembly stage 610 receives the input data 601 that specifies vertex data for high-order surfaces, primitives, or the like. The data assembly stage 610 collects the vertex data in a temporary storage or queue, such as by receiving a command from the host processor that includes a pointer to a buffer in memory and reading the vertex data from the buffer. The vertex data is then transmitted to the vertex shading stage 620 for processing.

The vertex shading stage 620 processes vertex data by performing a set of operations (e.g., a vertex shader or a program) once for each of the vertices. Vertices may be, e.g., specified as a 4-coordinate vector (e.g., <x, y, z, w>) associated with one or more vertex attributes (e.g., color, texture coordinates, surface normal, etc.). The vertex shading stage 620 may manipulate individual vertex attributes such as position, color, texture coordinates, and the like. In other words, the vertex shading stage 620 performs operations on the vertex coordinates or other vertex attributes associated with a vertex. Such operations commonly including lighting operations (e.g., modifying color attributes for a vertex) and transformation operations (e.g., modifying the coordinate space for a vertex). For example, vertices may be specified using coordinates in an object-coordinate space, which are transformed by multiplying the coordinates by a matrix that translates the coordinates from the object-coordinate space into a world space or a normalized-device-coordinate (NCD) space. The vertex shading stage 620 generates transformed vertex data that is transmitted to the primitive assembly stage 630.

The primitive assembly stage 630 collects vertices output by the vertex shading stage 620 and groups the vertices into geometric primitives for processing by the geometry shading stage 640. For example, the primitive assembly stage 630 may be configured to group every three consecutive vertices as a geometric primitive (e.g., a triangle) for transmission to the geometry shading stage 640. In some embodiments, specific vertices may be reused for consecutive geometric primitives (e.g., two consecutive triangles in a triangle strip may share two vertices). The primitive assembly stage 630 transmits geometric primitives (e.g., a collection of associated vertices) to the geometry shading stage 640.

The geometry shading stage 640 processes geometric primitives by performing a set of operations (e.g., a geometry shader or program) on the geometric primitives. Tessellation operations may generate one or more geometric primitives from each geometric primitive. In other words, the geometry shading stage 640 may subdivide each geometric primitive into a finer mesh of two or more geometric primitives for processing by the rest of the graphics processing pipeline 600. The geometry shading stage 640 transmits geometric primitives to the viewport SCC stage 650.

In an embodiment, the graphics processing pipeline 600 may operate within a streaming multiprocessor and the vertex shading stage 620, the primitive assembly stage 630, the geometry shading stage 640, the fragment shading stage 670, and/or hardware/software associated therewith, may sequentially perform processing operations. Once the sequential processing operations are complete, in an embodiment, the viewport SCC stage 650 may utilize the data. In an embodiment, primitive data processed by one or more of the stages in the graphics processing pipeline 600 may be written to a cache (e.g. L1 cache, a vertex cache, etc.). In this case, in an embodiment, the viewport SCC stage 650 may access the data in the cache. In an embodiment, the viewport SCC stage 650 and the rasterization stage 660 are implemented as fixed function circuitry.

The viewport SCC stage 650 performs viewport scaling, culling, and clipping of the geometric primitives. Each surface being rendered to is associated with an abstract camera position. The camera position represents a location of a viewer looking at the scene and defines a viewing frustum that encloses the objects of the scene. The viewing frustum may include a viewing plane, a rear plane, and four clipping planes. Any geometric primitive entirely outside of the viewing frustum may be culled (e.g., discarded) because the geometric primitive will not contribute to the final rendered scene. Any geometric primitive that is partially inside the viewing frustum and partially outside the viewing frustum may be clipped (e.g., transformed into a new geometric primitive that is enclosed within the viewing frustum. Furthermore, geometric primitives may each be scaled based on a depth of the viewing frustum. All potentially visible geometric primitives are then transmitted to the rasterization stage 660.

The rasterization stage 660 converts the 3D geometric primitives into 2D fragments (e.g. capable of being utilized for display, etc.). The rasterization stage 660 may be configured to utilize the vertices of the geometric primitives to setup a set of plane equations from which various attributes can be interpolated. The rasterization stage 660 may also compute a coverage mask for a plurality of pixels that indicates whether one or more sample locations for the pixel intercept the geometric primitive. In an embodiment, z-testing may also be performed to determine if the geometric primitive is occluded by other geometric primitives that have already been rasterized. The rasterization stage 660 generates fragment data (e.g., interpolated vertex attributes associated with a particular sample location for each covered pixel) that are transmitted to the fragment shading stage 670.

The fragment shading stage 670 processes fragment data by performing a set of operations (e.g., a fragment shader or a program) on each of the fragments. The fragment shading stage 670 may generate pixel data (e.g., color values) for the fragment such as by performing lighting operations or sampling texture maps using interpolated texture coordinates for the fragment. The fragment shading stage 670 generates pixel data that is transmitted to the raster operations stage 680.

The raster operations stage 680 may perform various operations on the pixel data such as performing alpha tests, stencil tests, and blending the pixel data with other pixel data corresponding to other fragments associated with the pixel. When the raster operations stage 680 has finished processing the pixel data (e.g., the output data 602), the pixel data may be written to a render target such as a frame buffer, a color buffer, or the like.

It will be appreciated that one or more additional stages may be included in the graphics processing pipeline 600 in addition to or in lieu of one or more of the stages described above. Various implementations of the abstract graphics processing pipeline may implement different stages. Furthermore, one or more of the stages described above may be excluded from the graphics processing pipeline in some embodiments (such as the geometry shading stage 640). Other types of graphics processing pipelines are contemplated as being within the scope of the present disclosure. Furthermore, any of the stages of the graphics processing pipeline 600 may be implemented by one or more dedicated hardware units within a graphics processor such as PPU 400. Other stages of the graphics processing pipeline 600 may be implemented by programmable hardware units such as the processing unit within the PPU 400.

The graphics processing pipeline 600 may be implemented via an application executed by a host processor, such as a CPU. In an embodiment, a device driver may implement an application programming interface (API) that defines various functions that can be utilized by an application in order to generate graphical data for display. The device driver is a software program that includes a plurality of instructions that control the operation of the PPU 400. The API provides an abstraction for a programmer that lets a programmer utilize specialized graphics hardware, such as the PPU 400, to generate the graphical data without requiring the programmer to utilize the specific instruction set for the PPU 400. The application may include an API call that is routed to the device driver for the PPU 400. The device driver interprets the API call and performs various operations to respond to the API call. In some instances, the device driver may perform operations by executing instructions on the CPU. In other instances, the device driver may perform operations, at least in part, by launching operations on the PPU 400 utilizing an input/output interface between the CPU and the PPU 400. In an embodiment, the device driver is configured to implement the graphics processing pipeline 600 utilizing the hardware of the PPU 400.

Various programs may be executed within the PPU 400 in order to implement the various stages of the graphics processing pipeline 600. For example, the device driver may launch a kernel on the PPU 400 to perform the vertex shading stage 620 on one processing unit (or multiple processing units). The device driver (or the initial kernel executed by the PPU 400) may also launch other kernels on the PPU 400 to perform other stages of the graphics processing pipeline 600, such as the geometry shading stage 640 and the fragment shading stage 670. In addition, some of the stages of the graphics processing pipeline 600 may be implemented on fixed unit hardware such as a rasterizer or a data assembler implemented within the PPU 400. It will be appreciated that results from one kernel may be processed by one or more intervening fixed function hardware units before being processed by a subsequent kernel on a processing unit.

Images generated applying one or more of the techniques disclosed herein may be displayed on a monitor or other display device. In some embodiments, the display device may be coupled directly to the system or processor generating or rendering the images. In other embodiments, the display device may be coupled indirectly to the system or processor such as via a network. Examples of such networks include the Internet, mobile telecommunications networks, a WIFI network, as well as any other wired and/or wireless networking system. When the display device is indirectly coupled, the images generated by the system or processor may be streamed over the network to the display device. Such streaming allows, for example, video games or other applications, which render images, to be executed on a server, a data center, or in a cloud-based computing environment and the rendered images to be transmitted and displayed on one or more user devices (such as a computer, video game console, smartphone, other mobile device, etc.) that are physically separate from the server or data center. Hence, the techniques disclosed herein can be applied to enhance the images that are streamed and to enhance services that stream images such as NVIDIA GeForce Now (GFN), Google Stadia, and the like.

Example Game Streaming System

FIG. 6B is an example system diagram for a game streaming system 605, in accordance with some embodiments of the present disclosure. FIG. 6B includes game server(s) 603 (which may include similar components, features, and/or functionality to the example processing system 500 of FIG. 5A and/or exemplary system 565 of FIG. 5B), client device(s) 604 (which may include similar components, features, and/or functionality to the example processing system 500 of FIG. 5A and/or exemplary system 565 of FIG. 5B), and network(s) 606 (which may be similar to the network(s) described herein). In some embodiments of the present disclosure, the system 605 may be implemented.

In the system 605, for a game session, the client device(s) 604 may only receive input data in response to inputs to the input device(s), transmit the input data to the game server(s) 603, receive encoded display data from the game server(s) 603, and display the display data on the display 624. As such, the more computationally intense computing and processing is offloaded to the game server(s) 603 (e.g., rendering—in particular ray or path tracing—for graphical output of the game session is executed by the GPU(s) of the game server(s) 603). In other words, the game session is streamed to the client device(s) 604 from the game server(s) 603, thereby reducing the requirements of the client device(s) 604 for graphics processing and rendering.

For example, with respect to an instantiation of a game session, a client device 604 may be displaying a frame of the game session on the display 624 based on receiving the display data from the game server(s) 603. The client device 604 may receive an input to one of the input device(s) and generate input data in response. The client device 604 may transmit the input data to the game server(s) 603 via the communication interface 621 and over the network(s) 606 (e.g., the Internet), and the game server(s) 603 may receive the input data via the communication interface 618. The CPU(s) may receive the input data, process the input data, and transmit data to the GPU(s) that causes the GPU(s) to generate a rendering of the game session. For example, the input data may be representative of a movement of a character of the user in a game, firing a weapon, reloading, passing a ball, turning a vehicle, etc. The rendering component 612 may render the game session (e.g., representative of the result of the input data) and the render capture component 614 may capture the rendering of the game session as display data (e.g., as image data capturing the rendered frame of the game session). The rendering of the game session may include ray or path-traced lighting and/or shadow effects, computed using one or more parallel processing units—such as GPUs, which may further employ the use of one or more dedicated hardware accelerators or processing cores to perform ray or path-tracing techniques—of the game server(s) 603. The encoder 616 may then encode the display data to generate encoded display data and the encoded display data may be transmitted to the client device 604 over the network(s) 606 via the communication interface 618. The client device 604 may receive the encoded display data via the communication interface 621 and the decoder 622 may decode the encoded display data to generate the display data. The client device 604 may then display the display data via the display 624.

It is noted that the techniques described herein may be embodied in executable instructions stored in a computer readable medium for use by or in connection with a processor-based instruction execution machine, system, apparatus, or device. It will be appreciated by those skilled in the art that, for some embodiments, various types of computer-readable media can be included for storing data. As used herein, a “computer-readable medium” includes one or more of any suitable media for storing the executable instructions of a computer program such that the instruction execution machine, system, apparatus, or device may read (or fetch) the instructions from the computer-readable medium and execute the instructions for carrying out the described embodiments. Suitable storage formats include one or more of an electronic, magnetic, optical, and electromagnetic format. A non-exhaustive list of conventional exemplary computer-readable medium includes: a portable computer diskette; a random-access memory (RAM); a read-only memory (ROM); an erasable programmable read only memory (EPROM); a flash memory device; and optical storage devices, including a portable compact disc (CD), a portable digital video disc (DVD), and the like.

It should be understood that the arrangement of components illustrated in the attached Figures are for illustrative purposes and that other arrangements are possible. For example, one or more of the elements described herein may be realized, in whole or in part, as an electronic hardware component. Other elements may be implemented in software, hardware, or a combination of software and hardware. Moreover, some or all of these other elements may be combined, some may be omitted altogether, and additional components may be added while still achieving the functionality described herein. Thus, the subject matter described herein may be embodied in many different variations, and all such variations are contemplated to be within the scope of the claims.

To facilitate an understanding of the subject matter described herein, many aspects are described in terms of sequences of actions. It will be recognized by those skilled in the art that the various actions may be performed by specialized circuits or circuitry, by program instructions being executed by one or more processors, or by a combination of both. The description herein of any sequence of actions is not intended to imply that the specific order described for performing that sequence must be followed. All methods described herein may be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.

The use of the terms “a” and “an” and “the” and similar references in the context of describing the subject matter (particularly in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context. Furthermore, the foregoing description is for the purpose of illustration only, and not for the purpose of limitation, as the scope of protection sought is defined by the claims as set forth hereinafter together with any equivalents thereof. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illustrate the subject matter and does not pose a limitation on the scope of the subject matter unless otherwise claimed. The use of the term “based on” and other like phrases indicating a condition for bringing about a result, both in the claims and in the written description, is not intended to foreclose any other conditions that bring about that result. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention as claimed. 

What is claimed is:
 1. A computer-implemented method for optimizing a reference three-dimensional (3D) model, comprising: processing an initial 3D model to produce a set of images for environmental conditions specifying at least one of camera position or light position; rendering the reference 3D model to produce a set of reference images for the environmental conditions; computing image space losses based on the set of images and the set of reference images; and updating parameters of the initial 3D model according to the image space losses to produce a reduced resolution 3D model having a lower geometric resolution compared with a geometric resolution of the reference 3D model.
 2. The computer-implemented method of claim 1, wherein the parameters comprise vertex locations and surface normal vectors.
 3. The computer-implemented method of claim 1, wherein a rendering pipeline that processes the initial 3D model to produce the set of images is a differentiable renderer and the image space losses are propagated backwards through the rendering pipeline to update the parameters.
 4. The computer-implemented method of claim 1, wherein a number of primitives defining the reduced resolution 3D model is equal or greater than a number of primitives defining the initial 3D model.
 5. The computer-implemented method of claim 4, wherein the number of primitives defining the reduced resolution 3D model is greater than the number of primitives defining the initial 3D model.
 6. The computer-implemented method of claim 1, wherein the parameters comprise materials.
 7. The computer-implemented method of claim 1, wherein the parameters comprise a normal map and geometric details of the reduced resolution 3D model are encoded into the normal map.
 8. The computer-implemented method of claim 1, wherein the parameters comprise spatially varying material parameters that approximate geometric details of the reduced resolution 3D model.
 9. The computer-implemented method of claim 1, wherein the reduced 3D model comprises a first geometric representation and the reference 3D model comprises a second geometric representation that is different from the first geometric representation.
 10. The computer-implemented method of claim 1, wherein the initial 3D model comprises a sphere.
 11. The computer-implemented method of claim 1, wherein the lower geometric resolution comprises a lower number of geometric primitives.
 12. The computer-implemented method of claim 11, wherein the lower geometric resolution further comprises a lower number of vertices.
 13. The computer-implemented method of claim 1, wherein the lower geometric resolution comprises a lower number of vertices.
 14. The computer-implemented method of claim 1, wherein the set of reference images comprise an animation sequence and the parameters comprise at least one of skinning weights and bone transformations.
 15. The computer-implemented method of claim 1, wherein at least one of the steps of processing, rendering, computing, and updating are performed within a cloud computing environment.
 16. The computer-implemented method of claim 1, wherein at least one of the steps of processing, rendering, computing, and updating are performed on a server or in a data center to generate the set of images and the reduced resolution 3D model is streamed to a user device.
 17. The computer-implemented method of claim 1, wherein at least one of the steps of processing, rendering, computing, and updating are performed for training, testing, or certifying a neural network employed in a machine, robot, or autonomous vehicle.
 18. The computer-implemented method of claim 1, wherein at least one of the steps of processing, rendering, computing, and updating is performed on a virtual machine comprising a portion of a graphics processing unit.
 19. A system, comprising: a processor that optimizes a reference three-dimensional (3D) model by: processing an initial 3D model to produce a set of images for environmental conditions specifying at least one of camera position or light position; rendering the reference 3D model to produce a set of reference images for the environmental conditions; computing image space losses based on the set of images and the set of reference images; and updating parameters of the initial 3D model according to the image space losses to produce a reduced resolution 3D model having a lower geometric resolution compared with a geometric resolution of the reference 3D model.
 20. The system of claim 19, wherein the lower geometric resolution comprises at least one of a lower number of vertices and a lower number of primitives.
 21. The system of claim 19, wherein the lower geometric resolution comprises both a lower number of vertices and a lower number of primitives.
 22. A non-transitory computer-readable media storing computer instructions for optimizing a reference three-dimensional (3D) model that, when executed by one or more processors, cause the one or more processors to perform the steps of: processing an initial 3D model to produce a set of images for environmental conditions specifying at least one of camera position or light position; rendering the reference 3D model to produce the set of reference images for the environmental conditions; computing image space losses based on a set of images and the set of reference images; and updating parameters of the initial 3D model according to the image space losses to produce a reduced resolution 3D model having a lower geometric resolution compared with a geometric resolution of the reference 3D model.
 23. The non-transitory computer-readable media of claim 22, wherein a number of primitives defining the reduced resolution 3D model is equal or greater than a number of primitives defining the initial 3D model. 